Dense fogs, with a visibility of less than 200 m, form a traffic hazard. Usually, models describing their formation use observations at the Cabauw super-site in the Netherlands for evaluation. A key parameter is the number of fog droplets and thus the number of aerosol particles on which the fog droplets form, the so-called fog nuclei (FN). No observational data are available for this key microphysical feature. An assumption is that this number scales with the concentration of the hygroscopic aerosol component sulfate. However, in the Netherlands nitrate and organics are the more important components of the total aerosol and thus possibly also of the FN. This short communication provides the first actual data via measurements with an aerosol mass spectrometer—AMS—for a period with dense fog events observed in November 2011. The aerosol in the relevant size range was composed of about half of the hygroscopic ammonium nitrate/sulfate. The other half consisted of organics; the low O/C ratio indicated that these compounds are rather hydrophobic; the hygroscopicity factor kappa of this mix was estimated at 0.3. This value implies that the activation diameter (the lowest diameter of the FN) was at least 150 nm. The mass distribution was converted into a number distribution which showed a sharp decrease as a function of size for diameters above this threshold. This result implies that the vast majority of the FN have diameters to the activation diameter. These smallest FN contained ammonium nitrate as the major hygroscopic compound. Currently, data for other dense fogs are evaluated to search for a possible generality of this finding.
{"title":"Dense Fog in the Netherlands: Composition of the Nuclei that Contribute Most to the Droplet Number Concentration","authors":"S. Crumeyrolle, P. Schlag, H. M. Ten Brink","doi":"10.30564/jasr.v7i3.6312","DOIUrl":"https://doi.org/10.30564/jasr.v7i3.6312","url":null,"abstract":"Dense fogs, with a visibility of less than 200 m, form a traffic hazard. Usually, models describing their formation use observations at the Cabauw super-site in the Netherlands for evaluation. A key parameter is the number of fog droplets and thus the number of aerosol particles on which the fog droplets form, the so-called fog nuclei (FN). No observational data are available for this key microphysical feature. An assumption is that this number scales with the concentration of the hygroscopic aerosol component sulfate. However, in the Netherlands nitrate and organics are the more important components of the total aerosol and thus possibly also of the FN. This short communication provides the first actual data via measurements with an aerosol mass spectrometer—AMS—for a period with dense fog events observed in November 2011. The aerosol in the relevant size range was composed of about half of the hygroscopic ammonium nitrate/sulfate. The other half consisted of organics; the low O/C ratio indicated that these compounds are rather hydrophobic; the hygroscopicity factor kappa of this mix was estimated at 0.3. This value implies that the activation diameter (the lowest diameter of the FN) was at least 150 nm. The mass distribution was converted into a number distribution which showed a sharp decrease as a function of size for diameters above this threshold. This result implies that the vast majority of the FN have diameters to the activation diameter. These smallest FN contained ammonium nitrate as the major hygroscopic compound. Currently, data for other dense fogs are evaluated to search for a possible generality of this finding.","PeriodicalId":193824,"journal":{"name":"Journal of Atmospheric Science Research","volume":"125 17","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141360479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Natan Chrysostomo de Oliveira Nogueira, Pedro Henrique Gomes Machado, Michelle Simões Reboita, A. L. Reis
The Intertropical Convergence Zone (ITCZ) is a key atmospheric system on a global scale, primarily driven by trade wind convergence near the equator. The ITCZ plays a crucial role in modulating the climate of the borders of tropical continental areas. For instance, Northeastern Brazil experiences a climate influenced by the ITCZ over the Atlantic Ocean. In some periods, the ITCZ exhibits double bands, known as the double ITCZ. While the features of the ITCZ have been described using various approaches and atmospheric variables, there is still a lack of regional studies focusing on the ITCZ and double ITCZ in the Atlantic Ocean. In this context, the main goals of this study are (1) to describe a simple algorithm based on precipitation to identify the ITCZ and double ITCZ, (2) to present a climatology (1997–2022) of the position, width, and intensity of these two convective bands, and (3) to investigate variabilities in the ITCZ characteristics associated with anomalies of sea surface temperature (SST) in the tropical Pacific and Atlantic oceans. The double ITCZ typically occurs southward of the main cloud band, and between February and April, both bands are more distant (~4.5°). In the western sector of the Atlantic Ocean, the ITCZ and its double band extend to more southerly latitudes in austral autumn. Considering the entire Atlantic basin, the annual mean of the latitudinal position, width, and intensity of the ITCZ is 4.9°N, 4.2°, and 11 mm/day, respectively, while for the double ITCZ, it is 0.4°N, 2.6°, 10.3 mm/day, respectively. While the SST anomalies in the Pacific Ocean (El Niño and La Niña episodes) affect more the ITCZ width, the SST anomalies in the Tropical South Atlantic affect both its position and width.
{"title":"Assessment of the Intertropical Convergence Zone over the Atlantic Ocean through an Algorithm Based on Precipitation","authors":"Natan Chrysostomo de Oliveira Nogueira, Pedro Henrique Gomes Machado, Michelle Simões Reboita, A. L. Reis","doi":"10.30564/jasr.v7i1.6188","DOIUrl":"https://doi.org/10.30564/jasr.v7i1.6188","url":null,"abstract":"The Intertropical Convergence Zone (ITCZ) is a key atmospheric system on a global scale, primarily driven by trade wind convergence near the equator. The ITCZ plays a crucial role in modulating the climate of the borders of tropical continental areas. For instance, Northeastern Brazil experiences a climate influenced by the ITCZ over the Atlantic Ocean. In some periods, the ITCZ exhibits double bands, known as the double ITCZ. While the features of the ITCZ have been described using various approaches and atmospheric variables, there is still a lack of regional studies focusing on the ITCZ and double ITCZ in the Atlantic Ocean. In this context, the main goals of this study are (1) to describe a simple algorithm based on precipitation to identify the ITCZ and double ITCZ, (2) to present a climatology (1997–2022) of the position, width, and intensity of these two convective bands, and (3) to investigate variabilities in the ITCZ characteristics associated with anomalies of sea surface temperature (SST) in the tropical Pacific and Atlantic oceans. The double ITCZ typically occurs southward of the main cloud band, and between February and April, both bands are more distant (~4.5°). In the western sector of the Atlantic Ocean, the ITCZ and its double band extend to more southerly latitudes in austral autumn. Considering the entire Atlantic basin, the annual mean of the latitudinal position, width, and intensity of the ITCZ is 4.9°N, 4.2°, and 11 mm/day, respectively, while for the double ITCZ, it is 0.4°N, 2.6°, 10.3 mm/day, respectively. While the SST anomalies in the Pacific Ocean (El Niño and La Niña episodes) affect more the ITCZ width, the SST anomalies in the Tropical South Atlantic affect both its position and width.","PeriodicalId":193824,"journal":{"name":"Journal of Atmospheric Science Research","volume":"2 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139609167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Huda Jamal Jumaah, A. Jasim, Aydin Rashid, Q. Ajaj
According to World Health Organization (WHO) estimates and based on a world population review, Iraq ranks tenth among the most air-polluted countries in the world. In this study, the authors tried to evaluate the outdoor air of Kirkuk City north of Iraq. The authors relied on two types of data: field measurements and remotely sensed data. Fifteen air quality points were determined in the study region representing the monthly average measurements implemented for the one-year dataset. Geographic information systems (GIS) based geo-statistic and geo-processing techniques have been applied to collected data. Spatial distribution data related to Air Quality Index (AQI), and Particulate Matter (PM10 and PM2.5) were obtained by mapping collected records. Remotely sensed data of PM2.5 were analyzed and compared with the collected data. Health impacts were assessed per each air pollutant determined in the study. Spatial distribution maps revealed the hazardous air type in the study area. Overall AQI ranged between 300 and 472 µg/m3 referring to unhealthy, very unhealthy, and hazardous classes of pollution. Also, PM10 ranged between 300 and 570 µg/m3 indicating the same class of air pollution from unhealthy to hazardous. While PM2.5 ranged between 40 and 60 µg/m3 which represents unhealthy air for sensitive persons and unhealthy air. The remotely sensed data revealed different air types for the study period ranging from 14.5 to 52.5 µg/m3 represented in moderate and unhealthy air for sensitive persons. Significant correlations were obtained where the mean local R2 (coefficient of determination) was obtained as 0.83. The assessed data were within high air pollution that requires immediate intervention for controlling causes and eliminating their effects.
{"title":"Air Pollution Risk Assessment Using GIS and Remotely Sensed Data in Kirkuk City, Iraq","authors":"Huda Jamal Jumaah, A. Jasim, Aydin Rashid, Q. Ajaj","doi":"10.30564/jasr.v6i3.5834","DOIUrl":"https://doi.org/10.30564/jasr.v6i3.5834","url":null,"abstract":"According to World Health Organization (WHO) estimates and based on a world population review, Iraq ranks tenth among the most air-polluted countries in the world. In this study, the authors tried to evaluate the outdoor air of Kirkuk City north of Iraq. The authors relied on two types of data: field measurements and remotely sensed data. Fifteen air quality points were determined in the study region representing the monthly average measurements implemented for the one-year dataset. Geographic information systems (GIS) based geo-statistic and geo-processing techniques have been applied to collected data. Spatial distribution data related to Air Quality Index (AQI), and Particulate Matter (PM10 and PM2.5) were obtained by mapping collected records. Remotely sensed data of PM2.5 were analyzed and compared with the collected data. Health impacts were assessed per each air pollutant determined in the study. Spatial distribution maps revealed the hazardous air type in the study area. Overall AQI ranged between 300 and 472 µg/m3 referring to unhealthy, very unhealthy, and hazardous classes of pollution. Also, PM10 ranged between 300 and 570 µg/m3 indicating the same class of air pollution from unhealthy to hazardous. While PM2.5 ranged between 40 and 60 µg/m3 which represents unhealthy air for sensitive persons and unhealthy air. The remotely sensed data revealed different air types for the study period ranging from 14.5 to 52.5 µg/m3 represented in moderate and unhealthy air for sensitive persons. Significant correlations were obtained where the mean local R2 (coefficient of determination) was obtained as 0.83. The assessed data were within high air pollution that requires immediate intervention for controlling causes and eliminating their effects.","PeriodicalId":193824,"journal":{"name":"Journal of Atmospheric Science Research","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128039141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The paper deals with the issues of differentiation of atmospheric precipitation into gradations according to their characteristics and established meteorological practices. The division of atmospheric precipitation into gradations allows one to have an idea of the possible consequences of their fallout on life in the area. The dependence of the average intensity of precipitation on their duration for the entire series of observations is not described by a power-law dependence with a sufficient degree of reliability, and when differentiating into gradations according to the amount of precipitation (< 2.5 mm, 2.5-10 mm, ≥ 10 mm), the dependences are obtained with a high degree of correlation. The scatter of points can be explained by the presence of intermediate categories of precipitation, which does not take into account the accepted division of the data. Thus, for large values of the amount of precipitation, the existence of a separate curve is possible, since the existing classifications of precipitation imply the division of heavy showers into separate gradations. Differentiation of rains by their duration shows a stronger stratification of the field of points for shorter rains (up to 60 minutes). This stratification of the field of points is successfully differentiated into shorter segments of 20, 30 minutes. Associated with the greater heterogeneity of shorter precipitation, it can be both rains of low intensity and heavy downpours of short duration. The probability of the position of the maximum intensity of precipitation during rain has more significant differences for precipitation less than 2.5 mm (the curves are more curved). For rains with a precipitation amount of 2.5 mm or more, the probability curves approach straight lines, which is associated with greater heterogeneity of precipitation less than 2.5 mm.
本文根据大气降水的特征和已有的气象实践，讨论了大气降水分级的问题。大气降水的等级划分使人们能够了解其沉降物对该地区生命的可能后果。在整个观测序列中，平均降水强度对持续时间的依赖关系不是用具有足够可靠性的幂律依赖关系来描述的，并且当根据降水量(< 2.5 mm, 2.5-10 mm，≥10 mm)划分为等级时，依赖性具有高度相关性。点的分散可以用降水的中间类别的存在来解释，这些类别没有考虑到可接受的数据划分。因此，对于较大的降水量，可能存在单独的曲线，因为现有的降水分类意味着将大阵雨划分为单独的等级。按持续时间区分的降雨表明，较短降雨(60分钟以内)的点场分层更强。这种点场的分层被成功地划分为20,30分钟的较短片段。与较短降水的更大异质性相关联，它既可以是低强度降雨，也可以是短时间的暴雨。对于小于2.5 mm的降水，降雨期间最大降水强度位置的概率差异更显著(曲线更弯曲)。对于降水量大于等于2.5 mm的降雨，概率曲线趋近于直线，这与小于2.5 mm的降水异质性较大有关。
{"title":"Relationship and Variability of Atmospheric Precipitation Characteristics in the North-West of Ukraine","authors":"S. V. Budnik","doi":"10.30564/jasr.v6i3.5657","DOIUrl":"https://doi.org/10.30564/jasr.v6i3.5657","url":null,"abstract":"The paper deals with the issues of differentiation of atmospheric precipitation into gradations according to their characteristics and established meteorological practices. The division of atmospheric precipitation into gradations allows one to have an idea of the possible consequences of their fallout on life in the area. The dependence of the average intensity of precipitation on their duration for the entire series of observations is not described by a power-law dependence with a sufficient degree of reliability, and when differentiating into gradations according to the amount of precipitation (< 2.5 mm, 2.5-10 mm, ≥ 10 mm), the dependences are obtained with a high degree of correlation. The scatter of points can be explained by the presence of intermediate categories of precipitation, which does not take into account the accepted division of the data. Thus, for large values of the amount of precipitation, the existence of a separate curve is possible, since the existing classifications of precipitation imply the division of heavy showers into separate gradations. Differentiation of rains by their duration shows a stronger stratification of the field of points for shorter rains (up to 60 minutes). This stratification of the field of points is successfully differentiated into shorter segments of 20, 30 minutes. Associated with the greater heterogeneity of shorter precipitation, it can be both rains of low intensity and heavy downpours of short duration. The probability of the position of the maximum intensity of precipitation during rain has more significant differences for precipitation less than 2.5 mm (the curves are more curved). For rains with a precipitation amount of 2.5 mm or more, the probability curves approach straight lines, which is associated with greater heterogeneity of precipitation less than 2.5 mm.","PeriodicalId":193824,"journal":{"name":"Journal of Atmospheric Science Research","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133315659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Meteorologists are experiencing many challenges in the reliable forecasting of the track and intensity of tropical cyclones (TC). Uses of the potential vorticity (PV) technique will enrich the current forecasting system. The use of PV analysis of TC intensification over the North Indian Ocean (NIO) is rare. In this study, the authors analyze the behaviour of upper-level PV with dynamic parameters of TCs over NIO. The authors used NCEP FNL reanalysis 1 × 1 degree data as input in WRF model version 4.0.3 with one-way nesting between the parent and child domains. The authors used a coupling of the Kain-Fritsch (new Eta) scheme and the WSM 6-class graupel scheme as cumulus and microphysics options to run the model. The authors found that at least 1 potential vorticity unit (PVU) (1 PVU = 10–6 m2 s –1KKg–1) upper PV is required to maintain the intensification of TC Titli. Larger upper PV accelerates the fall of central pressure. The high value of upper PV yields the intensification of TC. The wind shear and upper PV exhibited almost identical temporal evolution. Upper PV cannot intensify the TCs at negative wind shear and shear above the threshold value of 12 ms–1. The upper PV and geopotential heights of 500 hPa change mutually in opposite trends. The upper PV calculated by the model is comparable to that of ECMWF results. Therefore the findings of this study are admissible.
{"title":"Variation of Dynamical Parameters with Upper Tropospheric Potential Vorticity in Tropical Cyclone over the North Indian Ocean Using WRF Model","authors":"A. Rabbi, I. M. Syed, M. A. E. Akhter, M. Mallik","doi":"10.30564/jasr.v6i3.5717","DOIUrl":"https://doi.org/10.30564/jasr.v6i3.5717","url":null,"abstract":"Meteorologists are experiencing many challenges in the reliable forecasting of the track and intensity of tropical cyclones (TC). Uses of the potential vorticity (PV) technique will enrich the current forecasting system. The use of PV analysis of TC intensification over the North Indian Ocean (NIO) is rare. In this study, the authors analyze the behaviour of upper-level PV with dynamic parameters of TCs over NIO. The authors used NCEP FNL reanalysis 1 × 1 degree data as input in WRF model version 4.0.3 with one-way nesting between the parent and child domains. The authors used a coupling of the Kain-Fritsch (new Eta) scheme and the WSM 6-class graupel scheme as cumulus and microphysics options to run the model. The authors found that at least 1 potential vorticity unit (PVU) (1 PVU = 10–6 m2 s –1KKg–1) upper PV is required to maintain the intensification of TC Titli. Larger upper PV accelerates the fall of central pressure. The high value of upper PV yields the intensification of TC. The wind shear and upper PV exhibited almost identical temporal evolution. Upper PV cannot intensify the TCs at negative wind shear and shear above the threshold value of 12 ms–1. The upper PV and geopotential heights of 500 hPa change mutually in opposite trends. The upper PV calculated by the model is comparable to that of ECMWF results. Therefore the findings of this study are admissible.","PeriodicalId":193824,"journal":{"name":"Journal of Atmospheric Science Research","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132747160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The fragmented pattern and the rapidly declining preservation of older glacial features/evidences limits the precision, with which glacial chronologies can be established. The challenge is exacerbated by the scarcity of datable material and limitations of dating methods. Nevertheless, the preserved glacial landforms have been fairly utilized to establish glacial chronologies from different sectors of the Indian Himalayas. The existing Himalayan glacial chrono-stratigraphies have revealed that in a single valley, past glacial advances rarely surpass four stages. Thus, local and regional glacial chronologies must be synthesized to understand glacial dynamics and potential forcing factors. This research presents an overview of glacier responses to climate variations revealed by glacial chrono-stratigraphies in the western Indian Himalayan region over the Quaternary (late). The synthesis demonstrated that, although the glacial advances were sporadic, glaciers in western Himalayas generally advanced during the Marine isotope stage (MIS)-3/4, MIS-2, late glacial, Younger Dryas (YD) and Holocene periods. The Holocene has witnessed multiple glacial advances and the scatter is significant. While previous glacial research revealed that Himalayan glaciers were out of phase with the global last glacial maximum (gLGM), weak Indian Summer Monsoon (ISM) has been implicated (ISM was reduced by roughly 20%). Recent research, however, has shown that gLGM glaciation responded to the global cooling associated with the enhanced mid-latitude westerlies (MLW). Further, the magnitude of gLGM glacier advance varied along and across the Himalayas particularly the transitional valleys located between the ISM and MLW influence. It is also evident that both the ISM and MLW have governed the late Quaternary glacial advances in the western Himalayan region. However, the responses of glaciers to ISM changes are more prominent. The insights gained from this synthesis will help us understand the dynamics of glacier response to climate change, which will be valuable for future climate modelling.
{"title":"Role of Different Moisture Sources in Driving the Western Himalayan Past-glacier Advances","authors":"Prachita Arora, Sheikh Nawaz Ali, Anupam Sharma","doi":"10.30564/jasr.v6i3.5581","DOIUrl":"https://doi.org/10.30564/jasr.v6i3.5581","url":null,"abstract":"The fragmented pattern and the rapidly declining preservation of older glacial features/evidences limits the precision, with which glacial chronologies can be established. The challenge is exacerbated by the scarcity of datable material and limitations of dating methods. Nevertheless, the preserved glacial landforms have been fairly utilized to establish glacial chronologies from different sectors of the Indian Himalayas. The existing Himalayan glacial chrono-stratigraphies have revealed that in a single valley, past glacial advances rarely surpass four stages. Thus, local and regional glacial chronologies must be synthesized to understand glacial dynamics and potential forcing factors. This research presents an overview of glacier responses to climate variations revealed by glacial chrono-stratigraphies in the western Indian Himalayan region over the Quaternary (late). The synthesis demonstrated that, although the glacial advances were sporadic, glaciers in western Himalayas generally advanced during the Marine isotope stage (MIS)-3/4, MIS-2, late glacial, Younger Dryas (YD) and Holocene periods. The Holocene has witnessed multiple glacial advances and the scatter is significant. While previous glacial research revealed that Himalayan glaciers were out of phase with the global last glacial maximum (gLGM), weak Indian Summer Monsoon (ISM) has been implicated (ISM was reduced by roughly 20%). Recent research, however, has shown that gLGM glaciation responded to the global cooling associated with the enhanced mid-latitude westerlies (MLW). Further, the magnitude of gLGM glacier advance varied along and across the Himalayas particularly the transitional valleys located between the ISM and MLW influence. It is also evident that both the ISM and MLW have governed the late Quaternary glacial advances in the western Himalayan region. However, the responses of glaciers to ISM changes are more prominent. The insights gained from this synthesis will help us understand the dynamics of glacier response to climate change, which will be valuable for future climate modelling.","PeriodicalId":193824,"journal":{"name":"Journal of Atmospheric Science Research","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114316972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Especially for smallholder farmers with limited land and financial resources, farming in arid and semi-arid lands (ASALs), where season-to-season rainfall fluctuation dictates production, is a risky business. Through participatory approaches, this study compares deterministic and probabilistic interpretations of climate forecasts and their use by smallholder farmers through a crop-growing season. The study revealed that deterministic advisories are good for smallholder farmers only when formulated from forecasts with higher accuracy than the historical climatological distribution. Otherwise, they cause farm loss in terms of labor and inputs. On the other hand, probabilistic advisories help farmers spread the risk to cater to all the uncertainty and in so doing bring out a balance between confidence and caution. However, farmers must be supported with enough sensitization to comprehend forecast probability, translate it into probabilistic advisories and use that to plan and manage farm activities. The findings support the hypothesis providing packaged climate products in transparent probabilistic terms in place of deterministic form can overcome inherent credibility challenges. The study’s conclusion highlights important takeaways and new understandings of the advantage of using probabilistic advisories among resource-poor smallholder farmers.
{"title":"Co-designed Practical Use of Probabilistic Climate Advisories among Smallholder Farmers: A Balance between Confidence and Caution","authors":"Mary Mwangi, E. Kituyi, G. Ouma","doi":"10.30564/jasr.v6i2.5511","DOIUrl":"https://doi.org/10.30564/jasr.v6i2.5511","url":null,"abstract":"Especially for smallholder farmers with limited land and financial resources, farming in arid and semi-arid lands (ASALs), where season-to-season rainfall fluctuation dictates production, is a risky business. Through participatory approaches, this study compares deterministic and probabilistic interpretations of climate forecasts and their use by smallholder farmers through a crop-growing season. The study revealed that deterministic advisories are good for smallholder farmers only when formulated from forecasts with higher accuracy than the historical climatological distribution. Otherwise, they cause farm loss in terms of labor and inputs. On the other hand, probabilistic advisories help farmers spread the risk to cater to all the uncertainty and in so doing bring out a balance between confidence and caution. However, farmers must be supported with enough sensitization to comprehend forecast probability, translate it into probabilistic advisories and use that to plan and manage farm activities. The findings support the hypothesis providing packaged climate products in transparent probabilistic terms in place of deterministic form can overcome inherent credibility challenges. The study’s conclusion highlights important takeaways and new understandings of the advantage of using probabilistic advisories among resource-poor smallholder farmers.","PeriodicalId":193824,"journal":{"name":"Journal of Atmospheric Science Research","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121235948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The article is devoted to the discussion of the possibilities of approbation of one of the probabilistic methods of verification of evaluation works - the minimax method or the method of establishing the minimum risk of making erroneous diagnoses of the instability of the planetary boundary layer of air. Within the framework of this study, the task of probabilistic forecasting of diagnostic parameters and their combinations, leading in their totality to the formation of an unstable state of the planetary boundary layer of the atmosphere, was carried out. It is this state that, as shown by previous studies, a priori contribution to the development of a number of weather phenomena dangerous for society (squalls, hail, heavy rains, etc.). The results of applying the minimax method made it possible to identify a number of parameters, such as the intensity of circulation, the activity of the Earth’s magnetosphere, and the components of the geostrophic wind velocity, the combination of which led to the development of instability. In the future, it is possible to further expand the number of diagnosed parameters to identify more sensitive elements. In this sense, the minimax method, the usefulness of which is shown in this study, can be considered as one of the preparatory steps for the subsequent more detailed method for forecasting individual hazardous weather phenomena.
{"title":"The Possibilities of Using the Minimax Method to Diagnose the State of the Atmosphere","authors":"E. Andreeva","doi":"10.30564/jasr.v6i2.5519","DOIUrl":"https://doi.org/10.30564/jasr.v6i2.5519","url":null,"abstract":"The article is devoted to the discussion of the possibilities of approbation of one of the probabilistic methods of verification of evaluation works - the minimax method or the method of establishing the minimum risk of making erroneous diagnoses of the instability of the planetary boundary layer of air. Within the framework of this study, the task of probabilistic forecasting of diagnostic parameters and their combinations, leading in their totality to the formation of an unstable state of the planetary boundary layer of the atmosphere, was carried out. It is this state that, as shown by previous studies, a priori contribution to the development of a number of weather phenomena dangerous for society (squalls, hail, heavy rains, etc.). The results of applying the minimax method made it possible to identify a number of parameters, such as the intensity of circulation, the activity of the Earth’s magnetosphere, and the components of the geostrophic wind velocity, the combination of which led to the development of instability. In the future, it is possible to further expand the number of diagnosed parameters to identify more sensitive elements. In this sense, the minimax method, the usefulness of which is shown in this study, can be considered as one of the preparatory steps for the subsequent more detailed method for forecasting individual hazardous weather phenomena.","PeriodicalId":193824,"journal":{"name":"Journal of Atmospheric Science Research","volume":"41 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114107374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study examines long-term rainfall and temperature variations over a dry tropical environment in Nigeria. An assessment of the variations of these weather variables showcases the extent of climate change limits and corresponding effects on the biotic environment. Rainfall and temperature data were obtained from Nigerian Meteorological Agency for a period of 31 years (1991-2020) for Kano and Katsina States. Descriptive statistics were used to determine the degree of variability of the weather variables across spatial domains. Results showed that there is a sharp contrast in mean annual rainfall amounts of 1154.1 mm and 569.6 mm for Kano and Katsina located in the dry continental and semi-arid climate zones of Nigeria respectively. It is revealed that the month of August had the highest mean monthly rainfall for both areas i.e. 359 mm and 194 mm with little or no trace during the dry season. The sharp difference in rainfall amount across spatial domains of the near similar climate zones shows that the Inter-tropical Discontinuity (ITD) does not completely overwhelm the northern band of Nigeria in August. The least variable monthly rainfall was in August and July with coefficient variations (CV) of 40% and 47% for Kano and Katsina. The months of February and March had the highest CV of 557% and 273% for the respective areas. In the examined areas the wet and dry seasons are from June-September and October-May respectively. The index of rainfall variability and drought intensity for the areas ranged from 0.85-0.95 and 45% indicating moderate variability and drought respectively. Mean annual temperature values are 33.4 °C and 33.8 °C for Kano and Katsina. The study recommends a proper climate observing scheme, most especially for agrarian practices so as to ensure profitable outputs for human sustainability.
{"title":"Rainfall and Temperature Variations in a Dry Tropical Environment of Nigeria","authors":"D. Edokpa, P. Ede, B. Diagi, S. Ajiere","doi":"10.30564/jasr.v6i2.5527","DOIUrl":"https://doi.org/10.30564/jasr.v6i2.5527","url":null,"abstract":"This study examines long-term rainfall and temperature variations over a dry tropical environment in Nigeria. An assessment of the variations of these weather variables showcases the extent of climate change limits and corresponding effects on the biotic environment. Rainfall and temperature data were obtained from Nigerian Meteorological Agency for a period of 31 years (1991-2020) for Kano and Katsina States. Descriptive statistics were used to determine the degree of variability of the weather variables across spatial domains. Results showed that there is a sharp contrast in mean annual rainfall amounts of 1154.1 mm and 569.6 mm for Kano and Katsina located in the dry continental and semi-arid climate zones of Nigeria respectively. It is revealed that the month of August had the highest mean monthly rainfall for both areas i.e. 359 mm and 194 mm with little or no trace during the dry season. The sharp difference in rainfall amount across spatial domains of the near similar climate zones shows that the Inter-tropical Discontinuity (ITD) does not completely overwhelm the northern band of Nigeria in August. The least variable monthly rainfall was in August and July with coefficient variations (CV) of 40% and 47% for Kano and Katsina. The months of February and March had the highest CV of 557% and 273% for the respective areas. In the examined areas the wet and dry seasons are from June-September and October-May respectively. The index of rainfall variability and drought intensity for the areas ranged from 0.85-0.95 and 45% indicating moderate variability and drought respectively. Mean annual temperature values are 33.4 °C and 33.8 °C for Kano and Katsina. The study recommends a proper climate observing scheme, most especially for agrarian practices so as to ensure profitable outputs for human sustainability.","PeriodicalId":193824,"journal":{"name":"Journal of Atmospheric Science Research","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131090964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Senghor, A. Dieng, Moussa Gueye, C. Diop, M. Kane, A. Gaye
This research studies the capability of the Weather Research and Forecasting model coupled with the Chemistry/Aerosol module (WRF-Chem) with and without parametrization to reproduce a dust storm, which was held on 27th June 2018 over Sahara region. The authors use satellite observations and ground-based measurements to evaluate the WRF-Chem simulations. The sensitivities of WRF-Chem Model are tested on the replication of haboob features with a tuned GOCART aerosol module. Comparisons of simulations with satellite and ground-based observations show that WRF-Chem is able to reproduce the Aerosol Optical Depth (AOD) distribution and associated changes of haboob in the meteorological fields with temperature drops of about 9 °C and wind gust 20 m·s–1. The WRF-Chem Convection-permitting model (CPM) shows strong 10-meter winds induced a large dust emission along the leading edge of a convective cold pool (LECCP). The CPM indicates heavy dust transported over the West African coast (16°W-10°W; 6°N-21°N) which has a potential for long-distance travel on 27th June between 1100 UTC and 1500 UTC. The daily precipitation is improved in the CPM with a spatial distribution similar to the GPM-IMERG precipitation and maximum rainfall located at the right place. As well as raising a large amount of dust, the haboob caused considerable damage along its route.
{"title":"Formation and Transport of a Saharan Dust Plume in Early Summer","authors":"H. Senghor, A. Dieng, Moussa Gueye, C. Diop, M. Kane, A. Gaye","doi":"10.30564/jasr.v6i2.5407","DOIUrl":"https://doi.org/10.30564/jasr.v6i2.5407","url":null,"abstract":"This research studies the capability of the Weather Research and Forecasting model coupled with the Chemistry/Aerosol module (WRF-Chem) with and without parametrization to reproduce a dust storm, which was held on 27th June 2018 over Sahara region. The authors use satellite observations and ground-based measurements to evaluate the WRF-Chem simulations. The sensitivities of WRF-Chem Model are tested on the replication of haboob features with a tuned GOCART aerosol module. Comparisons of simulations with satellite and ground-based observations show that WRF-Chem is able to reproduce the Aerosol Optical Depth (AOD) distribution and associated changes of haboob in the meteorological fields with temperature drops of about 9 °C and wind gust 20 m·s–1. The WRF-Chem Convection-permitting model (CPM) shows strong 10-meter winds induced a large dust emission along the leading edge of a convective cold pool (LECCP). The CPM indicates heavy dust transported over the West African coast (16°W-10°W; 6°N-21°N) which has a potential for long-distance travel on 27th June between 1100 UTC and 1500 UTC. The daily precipitation is improved in the CPM with a spatial distribution similar to the GPM-IMERG precipitation and maximum rainfall located at the right place. As well as raising a large amount of dust, the haboob caused considerable damage along its route.","PeriodicalId":193824,"journal":{"name":"Journal of Atmospheric Science Research","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133848953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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