Marco Antonio Mora-Ramírez, Edgar Martínez-Luna, Xochitl Cruz-Núñez
The Megalopolis of Central Mexico experiences high levels above the Official Mexican Standard (NOM) of PM2.5, leading to various respiratory diseases ranging from acute symptoms to chronic illnesses such as asthma and lung cancer. It is crucial to measure PM2.5 levels accurately to warn the public about the risks of exposure to particulate matter. Unfortunately, the Megalopolis of Central Mexico has a shortage of monitoring sites, limiting data availability. This study addresses this issue using satellite data to develop a multiple linear regression model. Our model uses aerosol optical depth (AOD), relative humidity (RH), temperature (T), the planetary boundary layer height (PBLH), and the normalized difference vegetation index (NDVI) as independent variables to estimate PM2.5 concentrations in the region under study. The relationship between AOD and PM2.5 concentrations was found to be strongly influenced by RH and T. However, this effect is compensated for by a low PBLH (< 400 m), which enables AOD and PM2.5 measurements to be similar in magnitude. Our findings have important implications for estimating PM2.5 concentrations using satellite data. This study could help improve air quality monitoring in the Megalopolis of Central Mexico by providing more spatial and temporal data on particle concentrations in the atmosphere.
{"title":"Satellite data geoprocessing to estimate PM2.5 over the Megalopolis of Central Mexico","authors":"Marco Antonio Mora-Ramírez, Edgar Martínez-Luna, Xochitl Cruz-Núñez","doi":"10.20937/atm.53227","DOIUrl":"https://doi.org/10.20937/atm.53227","url":null,"abstract":"The Megalopolis of Central Mexico experiences high levels above the Official Mexican Standard (NOM) of PM2.5, leading to various respiratory diseases ranging from acute symptoms to chronic illnesses such as asthma and lung cancer. It is crucial to measure PM2.5 levels accurately to warn the public about the risks of exposure to particulate matter. Unfortunately, the Megalopolis of Central Mexico has a shortage of monitoring sites, limiting data availability. This study addresses this issue using satellite data to develop a multiple linear regression model. Our model uses aerosol optical depth (AOD), relative humidity (RH), temperature (T), the planetary boundary layer height (PBLH), and the normalized difference vegetation index (NDVI) as independent variables to estimate PM2.5 concentrations in the region under study. The relationship between AOD and PM2.5 concentrations was found to be strongly influenced by RH and T. However, this effect is compensated for by a low PBLH (< 400 m), which enables AOD and PM2.5 measurements to be similar in magnitude. Our findings have important implications for estimating PM2.5 concentrations using satellite data. This study could help improve air quality monitoring in the Megalopolis of Central Mexico by providing more spatial and temporal data on particle concentrations in the atmosphere.","PeriodicalId":55576,"journal":{"name":"Atmosfera","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135815332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Snow has great environmental importance. Its physical properties influence the ground temperature; its long-term accumulation adds to the mass of glaciers and is also a clear indicator of climate variability. However, despite the frequency of snowfall in tropical high-mountain environments, its quantitative study is very scarce, and it is non-existent in the case of Mexico. Due to the altitude of a large part of the Mexican territory and the high ecosystem value of the snow, in this work we analyze the temporality, accumulation, and duration of the snow cover on the highest mountain in the country. The data obtained through continuous monitoring of the surface temperature of the ground allowed us to identify that snowfall occurs with greater frequency and volume during the summer and autumn months, while during the winter snowfall of less intensity occurs. The accumulation values are mostly less than 30 cm thick, and the duration of the snowpack is on average less than two weeks; however, there are episodes of greater depth and duration.
{"title":"Occurrence and characteristics of snowfall on the highest mountain of Mexico (Citlaltépetl volcano) through the ground’s surface temperature","authors":"Victor Soto, Hugo Delgado Granados","doi":"10.20937/atm.53204","DOIUrl":"https://doi.org/10.20937/atm.53204","url":null,"abstract":"Snow has great environmental importance. Its physical properties influence the ground temperature; its long-term accumulation adds to the mass of glaciers and is also a clear indicator of climate variability. However, despite the frequency of snowfall in tropical high-mountain environments, its quantitative study is very scarce, and it is non-existent in the case of Mexico. Due to the altitude of a large part of the Mexican territory and the high ecosystem value of the snow, in this work we analyze the temporality, accumulation, and duration of the snow cover on the highest mountain in the country. The data obtained through continuous monitoring of the surface temperature of the ground allowed us to identify that snowfall occurs with greater frequency and volume during the summer and autumn months, while during the winter snowfall of less intensity occurs. The accumulation values are mostly less than 30 cm thick, and the duration of the snowpack is on average less than two weeks; however, there are episodes of greater depth and duration.","PeriodicalId":55576,"journal":{"name":"Atmosfera","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135464464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
One of the impacts of climate change is an increase in the frequency and intensity of hydrometeorological disasters such as prolonged droughts. Borneo is one of the areas threatened by drought due to climate change. Therefore, it is important to identify and implement appropriate mitigation and adaptation measures. This study used the dynamical downscaling method by the Conformal Cubic Atmospheric Model (CCAM) to evaluate the potential for drought events in Borneo based on the RCP 4.5 scenario. The annual rainfall in Borneo for 2021-2050 is projected to increase compared to 1991-2020. However, the increase in annual rainfall does not free Borneo from the possibility of drought events in the future. This study’s results indicate that areas in southern Borneo, such as Banjarmasin, Pangkalan Bun, and Pontianak, will have a higher frequency of meteorological drought events and are also expected to experience longer periods of consecutive dry days between 2021-2050 compared to 1991-2020.
{"title":"Drought Potential in Borneo Based on the RCP 4.5 Scenario","authors":"Amalia Nurlatifah, Fildzah Adany, Aulia Darojatun, Bambang Siswanto, Sinta Berliana Sipayung","doi":"10.20937/atm.53185","DOIUrl":"https://doi.org/10.20937/atm.53185","url":null,"abstract":"One of the impacts of climate change is an increase in the frequency and intensity of hydrometeorological disasters such as prolonged droughts. Borneo is one of the areas threatened by drought due to climate change. Therefore, it is important to identify and implement appropriate mitigation and adaptation measures. This study used the dynamical downscaling method by the Conformal Cubic Atmospheric Model (CCAM) to evaluate the potential for drought events in Borneo based on the RCP 4.5 scenario. The annual rainfall in Borneo for 2021-2050 is projected to increase compared to 1991-2020. However, the increase in annual rainfall does not free Borneo from the possibility of drought events in the future. This study’s results indicate that areas in southern Borneo, such as Banjarmasin, Pangkalan Bun, and Pontianak, will have a higher frequency of meteorological drought events and are also expected to experience longer periods of consecutive dry days between 2021-2050 compared to 1991-2020.","PeriodicalId":55576,"journal":{"name":"Atmosfera","volume":"04 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135464465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A flood map simulation in the Fenton River watershed, Connecticut, was conducted for Tropical Storm Elsa occurred in early July 2021, using Multi Radar Multi Sensor-Quantitative Precipitation Estimation (MRMS-QPE) as input to force the Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) to simulate discharges in the mainstream of the watershed. The simulated discharges were calibrated using observed discharges at the Old Turnpike Bridge USGS station, and they were used to force a Hydrologic Engineering Center-River Analysis System (HEC-RAS) 2D model of the Fenton River watershed. The simulated stages were calibrated using observed stages at Old Turnpike Bridge USGS station to simulate flood maps in the mainstream of the watershed. The resulting use of HEC-HMS and HEC-RAS 2D models coupled with MRMS-QPE precipitation shows that these models set up is user-friendly. The model shows stability and the capacity to simulate flood maps along the whole mainstream of the Fenton River with good accuracy.
{"title":"Modeling tropical storm Elsa: Flood map simulation using multisensory precipitation in Connecticut","authors":"J. Stella","doi":"10.20937/atm.53234","DOIUrl":"https://doi.org/10.20937/atm.53234","url":null,"abstract":"A flood map simulation in the Fenton River watershed, Connecticut, was conducted for Tropical Storm Elsa occurred in early July 2021, using Multi Radar Multi Sensor-Quantitative Precipitation Estimation (MRMS-QPE) as input to force the Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) to simulate discharges in the mainstream of the watershed. The simulated discharges were calibrated using observed discharges at the Old Turnpike Bridge USGS station, and they were used to force a Hydrologic Engineering Center-River Analysis System (HEC-RAS) 2D model of the Fenton River watershed. The simulated stages were calibrated using observed stages at Old Turnpike Bridge USGS station to simulate flood maps in the mainstream of the watershed. The resulting use of HEC-HMS and HEC-RAS 2D models coupled with MRMS-QPE precipitation shows that these models set up is user-friendly. The model shows stability and the capacity to simulate flood maps along the whole mainstream of the Fenton River with good accuracy.","PeriodicalId":55576,"journal":{"name":"Atmosfera","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43499456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Louise da Fonseca Aguiar, M. Cataldi, E. Marton, Eric Miguel Ribeiro, Priscila da Cunha Luz
The South Atlantic Convergence Zone (SACZ) is an atmospheric phenomenon typical of summertime where a band of nebulosity causes intense or persistent rainfall in many regions of Brazil. SACZ episodes can be responsible for many natural disasters. Besides, the impacts of rainfall on water availability and consequently on the energy sector are extensive. The main objective of this study was to investigate the implementation of the SACZ index as an objective forecasting tool using input data from the Global Forecast System (GFS) model. Initially, we compared the index with the SACZ events identified by the Center for Weather Forecasting and Climate Studies (CPTEC ) from 2017 to 2021. Results showed that the index represented all events identified SACZs by CPTEC. Finally, we used data from the GFS 0.25 Degree from 2017 to 2021 to calculate Accuracy, Probability of detection, and False alarm ratio to evaluate the SACZ index as a prediction tool. Three thresholds are defined for the binary classification of a possible SACZ event. Results showed that above the most sensitive threshold (h1), within 10 days in advance, the sign of a possible SACZ can be detected. For the intermediate threshold (h2), a forecast of 96 h can detect a sign. For the most specific threshold (h3), the index can detect the event within 72 h in advance with a probability of detection of almost 90%. The SACZ index proved to be an efficient tool for detecting the dynamics of the phenomenon and can be used to assist operationally and in decision-making.
{"title":"Evaluation of the SACZ index as a prognostic tool based on GFS forecasts","authors":"Louise da Fonseca Aguiar, M. Cataldi, E. Marton, Eric Miguel Ribeiro, Priscila da Cunha Luz","doi":"10.20937/atm.53248","DOIUrl":"https://doi.org/10.20937/atm.53248","url":null,"abstract":"The South Atlantic Convergence Zone (SACZ) is an atmospheric phenomenon typical of summertime where a band of nebulosity causes intense or persistent rainfall in many regions of Brazil. SACZ episodes can be responsible for many natural disasters. Besides, the impacts of rainfall on water availability and consequently on the energy sector are extensive. The main objective of this study was to investigate the implementation of the SACZ index as an objective forecasting tool using input data from the Global Forecast System (GFS) model. Initially, we compared the index with the SACZ events identified by the Center for Weather Forecasting and Climate Studies (CPTEC ) from 2017 to 2021. Results showed that the index represented all events identified SACZs by CPTEC. Finally, we used data from the GFS 0.25 Degree from 2017 to 2021 to calculate Accuracy, Probability of detection, and False alarm ratio to evaluate the SACZ index as a prediction tool. Three thresholds are defined for the binary classification of a possible SACZ event. Results showed that above the most sensitive threshold (h1), within 10 days in advance, the sign of a possible SACZ can be detected. For the intermediate threshold (h2), a forecast of 96 h can detect a sign. For the most specific threshold (h3), the index can detect the event within 72 h in advance with a probability of detection of almost 90%. The SACZ index proved to be an efficient tool for detecting the dynamics of the phenomenon and can be used to assist operationally and in decision-making.","PeriodicalId":55576,"journal":{"name":"Atmosfera","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43439138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lainer Felipe Donet Vasconcellos, Lester Augusto Alfonso Diaz
There are a few three-moment schemes that consider other processes besides sedimentation. Thus, a performance assessment of these types of schemes due to the combined effect of sedimentation and other microphysical processes is a matter of interest. In this study, a warm rain bulk three-moment parameterized scheme was developed and evaluated through a detailed comparison with a bin microphysical scheme. To evaluate the impact of sedimentation and the combined effect of sedimentation and collision-coalescence on the droplet size distribution (DSD), a rain shaft model was applied to the DSD with different initial values of the shape parameter. For pure sedimentation, a good correspondence was obtained between the three-moment scheme and the explicit model, with a practically perfect coincidence of bulk quantities for larger values of the gamma distribution’s initial shape parameter and, in general, the three-moment parameterization scheme performing much better than the two-moment scheme. The simulations performed for this case confirm (as reported in previous studies) that for pure sedimentation, the three-moment parameterization schemes deliver a physically more complete representation of the evolution of droplet size distribution. The impact of the combined effect of sedimentation and collision-coalescence processes on DSD was also assessed. We could observe that certain differences arise between the parameterized scheme and the spectral model when the collision-coalescence process is incorporated, as the onset of precipitation occurs earlier in the three-moment parameterized scheme. It can be concluded that, in general, the three-moment warm rain bulk microphysics scheme is able to reproduce the results of the reference bin microphysical model.
{"title":"Development and evaluation of a bulk three-moment parameterization scheme incorporating the processes of sedimentation and collision-coalescence","authors":"Lainer Felipe Donet Vasconcellos, Lester Augusto Alfonso Diaz","doi":"10.20937/atm.53181","DOIUrl":"https://doi.org/10.20937/atm.53181","url":null,"abstract":"There are a few three-moment schemes that consider other processes besides sedimentation. Thus, a performance assessment of these types of schemes due to the combined effect of sedimentation and other microphysical processes is a matter of interest. In this study, a warm rain bulk three-moment parameterized scheme was developed and evaluated through a detailed comparison with a bin microphysical scheme. To evaluate the impact of sedimentation and the combined effect of sedimentation and collision-coalescence on the droplet size distribution (DSD), a rain shaft model was applied to the DSD with different initial values of the shape parameter. For pure sedimentation, a good correspondence was obtained between the three-moment scheme and the explicit model, with a practically perfect coincidence of bulk quantities for larger values of the gamma distribution’s initial shape parameter and, in general, the three-moment parameterization scheme performing much better than the two-moment scheme. The simulations performed for this case confirm (as reported in previous studies) that for pure sedimentation, the three-moment parameterization schemes deliver a physically more complete representation of the evolution of droplet size distribution. The impact of the combined effect of sedimentation and collision-coalescence processes on DSD was also assessed. We could observe that certain differences arise between the parameterized scheme and the spectral model when the collision-coalescence process is incorporated, as the onset of precipitation occurs earlier in the three-moment parameterized scheme. It can be concluded that, in general, the three-moment warm rain bulk microphysics scheme is able to reproduce the results of the reference bin microphysical model.","PeriodicalId":55576,"journal":{"name":"Atmosfera","volume":"123 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135464466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Judith Rodrigues Cardoso, E. Marton, Flávia Rodrigues Pinheiro, William Cossich, Nilton Oliveira Moraes
Fog is an atmospheric phenomenon that reduces horizontal visibility to 1000 m or less. These phenomena affect different human activities, mainly those associated with air, maritime, and road transport. Rio Grande city, located in southern Brazil, has one of the main Brazilian ports, and fog occurrences at this location cause several inconveniences, such as the interruption of port activities and increases in operating costs. Thus, a better understanding of fog formation and dissipation, and the consequent improvement in its forecasts, can bring significant help to the port activities in that region. Therefore, this work seeks to evaluate the WRF model’s ability to simulate fog events in Rio Grande city. Four study cases of dense fogs were performed for this goal, as well as a sensitivity test to select the best vertical resolution configuration of the model. Meteorological data from the Rio Grande pilotage station and the Brazilian Coastal Monitoring System buoys were analyzed. Satellite images and synoptic charts were also analyzed for the study cases. The numerical simulations were performed using the WRF model with three nested domains, where 1 km was the highest horizontal resolution. The Fog Stability Index (FSI) and two estimates of horizontal visibility were evaluated. Simulations show promising results, highlighting the ability of the model to identify the fog occurrence in the area of interest and represent aspects of its dissipation process. Furthermore, it is noteworthy that the FSI and the evaluated visibility estimates were sensitive to the occurrence of the events.
{"title":"Dense fog simulation in southern Brazil using the WRF model with high spatial resolution","authors":"Judith Rodrigues Cardoso, E. Marton, Flávia Rodrigues Pinheiro, William Cossich, Nilton Oliveira Moraes","doi":"10.20937/atm.53232","DOIUrl":"https://doi.org/10.20937/atm.53232","url":null,"abstract":"Fog is an atmospheric phenomenon that reduces horizontal visibility to 1000 m or less. These phenomena affect different human activities, mainly those associated with air, maritime, and road transport. Rio Grande city, located in southern Brazil, has one of the main Brazilian ports, and fog occurrences at this location cause several inconveniences, such as the interruption of port activities and increases in operating costs. Thus, a better understanding of fog formation and dissipation, and the consequent improvement in its forecasts, can bring significant help to the port activities in that region. Therefore, this work seeks to evaluate the WRF model’s ability to simulate fog events in Rio Grande city. Four study cases of dense fogs were performed for this goal, as well as a sensitivity test to select the best vertical resolution configuration of the model. Meteorological data from the Rio Grande pilotage station and the Brazilian Coastal Monitoring System buoys were analyzed. Satellite images and synoptic charts were also analyzed for the study cases. The numerical simulations were performed using the WRF model with three nested domains, where 1 km was the highest horizontal resolution. The Fog Stability Index (FSI) and two estimates of horizontal visibility were evaluated. Simulations show promising results, highlighting the ability of the model to identify the fog occurrence in the area of interest and represent aspects of its dissipation process. Furthermore, it is noteworthy that the FSI and the evaluated visibility estimates were sensitive to the occurrence of the events.","PeriodicalId":55576,"journal":{"name":"Atmosfera","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41711231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This work aimed to identify the synoptic conditions associated with the cold fronts (CFs) passage that causes intense winds in the Santos Basin. Furthermore, the atmospheric characteristics of the CFs, which generated intense (INTW) and moderate (MODW) winds in the studied area, were identified. For this purpose, INTW and MODW composites of CFs episodes were elaborated. First, the INTW and MODW cases were selected from the 10 m wind intensity observed in the Santos buoy, belonging to the Brazilian National Buoys Program. Satellite images and synoptic surface charts were analyzed to identify the synoptic systems responsible for INTW and MODW in the Santos buoy, keeping only the cases generated by CFs. From the comparison between the composites, it was possible to observe in INTW: (i) a stronger pressure gradient over the Santos Basin, with the isobars presenting an almost meridional position near the basin, which caused the intense winds registered in the buoy; (ii) a baroclinic trough at medium and high levels reaching the Santos Basin region, located westward of the surface system; (iii) stronger 1000-500 hPa layer thickness and dew point temperature gradients over the continent, reaching the Santos Basin region, and (iv) a colder and drier air mass over southern Brazil. On a large scale, the Rossby wave tracings were analyzed, where different wavenumbers were noticed for each composite. In INTW, the wavenumber was 2, while in MODW, it was 2 and 3. Finally, the main characteristics found in the composites were observed in the case studies.
{"title":"Cold fronts responsible for intense winds in the Santos Basin, Brazilian Southeast Offshore Region","authors":"Jamyle Magalhães Jamyle Magalhães, Fernanda Cerqueira Vasconcellos, Claudine Pereira Dereczynski, Amanda Rehbein, Michelle Simões Reboita","doi":"10.20937/atm.53187","DOIUrl":"https://doi.org/10.20937/atm.53187","url":null,"abstract":"This work aimed to identify the synoptic conditions associated with the cold fronts (CFs) passage that causes intense winds in the Santos Basin. Furthermore, the atmospheric characteristics of the CFs, which generated intense (INTW) and moderate (MODW) winds in the studied area, were identified. For this purpose, INTW and MODW composites of CFs episodes were elaborated. First, the INTW and MODW cases were selected from the 10 m wind intensity observed in the Santos buoy, belonging to the Brazilian National Buoys Program. Satellite images and synoptic surface charts were analyzed to identify the synoptic systems responsible for INTW and MODW in the Santos buoy, keeping only the cases generated by CFs. From the comparison between the composites, it was possible to observe in INTW: (i) a stronger pressure gradient over the Santos Basin, with the isobars presenting an almost meridional position near the basin, which caused the intense winds registered in the buoy; (ii) a baroclinic trough at medium and high levels reaching the Santos Basin region, located westward of the surface system; (iii) stronger 1000-500 hPa layer thickness and dew point temperature gradients over the continent, reaching the Santos Basin region, and (iv) a colder and drier air mass over southern Brazil. On a large scale, the Rossby wave tracings were analyzed, where different wavenumbers were noticed for each composite. In INTW, the wavenumber was 2, while in MODW, it was 2 and 3. Finally, the main characteristics found in the composites were observed in the case studies.","PeriodicalId":55576,"journal":{"name":"Atmosfera","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135215636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Validation of gridded precipitation products (GPP) increases the users’ confidence and highlights possible improvements in the algorithms to handle complex rain-forming processes. We evaluated the skill of three GGPs (CHIRPS-v2, CHELSA, and TerraClimate) in estimating the rain gauge observations and compared the precipitation trends derived from these products across the East and Southern Africa (ESA) region. We used Taylor diagrams and Kling-Gupta Efficiency (KGE) to assess the accuracy. A modified Mann-Kendal test and a Sen’s slope estimator were utilized to determine the trends’ significance and magnitude, respectively. The three GPPs had varied performance over temporal and altitudinal ranges. The skill of the three GPPs, at a monthly scale, was generally high but showed lower performance at elevations over 1500 masl, especially during the October-November-December (OND) season. The three GPPs performed equally well between the 1001 – 1500 masl elevation range. CHELSA-v2.1 was most accurate at 0-500 masl but had the lowest skill in both 501 – 1000 and above 1500 masl elevations, which caused over-estimation of the annual and seasonal precipitation trends over mountainous terrain and large inland water bodies. The quantified precipitation trends revealed high spatial-temporal variability. Generally, the skill and precipitation trends derived from CHIRPS-v2 and TC data showed substantial convergence except in Tanzania. Our results emphasize the importance of validating climate datasets to avoid error propagation in different models and applications. Moreover, we demonstrate that new or higher-resolution precipitation data are not always accurate since an algorithm update can introduce artifacts or biases.
{"title":"Assessing the skill of gridded satellite and reanalysis precipitation products over in East and Southern Africa","authors":"Francis Kamau Muthoni, Exavery Kigosi","doi":"10.20937/atm.53177","DOIUrl":"https://doi.org/10.20937/atm.53177","url":null,"abstract":"Validation of gridded precipitation products (GPP) increases the users’ confidence and highlights possible improvements in the algorithms to handle complex rain-forming processes. We evaluated the skill of three GGPs (CHIRPS-v2, CHELSA, and TerraClimate) in estimating the rain gauge observations and compared the precipitation trends derived from these products across the East and Southern Africa (ESA) region. We used Taylor diagrams and Kling-Gupta Efficiency (KGE) to assess the accuracy. A modified Mann-Kendal test and a Sen’s slope estimator were utilized to determine the trends’ significance and magnitude, respectively. The three GPPs had varied performance over temporal and altitudinal ranges. The skill of the three GPPs, at a monthly scale, was generally high but showed lower performance at elevations over 1500 masl, especially during the October-November-December (OND) season. The three GPPs performed equally well between the 1001 – 1500 masl elevation range. CHELSA-v2.1 was most accurate at 0-500 masl but had the lowest skill in both 501 – 1000 and above 1500 masl elevations, which caused over-estimation of the annual and seasonal precipitation trends over mountainous terrain and large inland water bodies. The quantified precipitation trends revealed high spatial-temporal variability. Generally, the skill and precipitation trends derived from CHIRPS-v2 and TC data showed substantial convergence except in Tanzania. Our results emphasize the importance of validating climate datasets to avoid error propagation in different models and applications. Moreover, we demonstrate that new or higher-resolution precipitation data are not always accurate since an algorithm update can introduce artifacts or biases.","PeriodicalId":55576,"journal":{"name":"Atmosfera","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135657265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yousef Ramezani, Mohammad Nazeri Tahroudi, Matina Pronoos Sedighi
In this study, the accuracy of the copula-based model in the simulation of the dew point temperature in various climates of Iran was investigated, using simulations based on vine copulas such as C-, D-, and R-vine copulas. By examining the various vine copulas and their tree sequences, the best copula and best tree sequence based on AIC, BIC, and log-likelihood were selected. The results show that based on the complete similarity in our case between C-, D- and R-vine copulas, the selected best C-vine copulas fit well the dependence between the minimum and maximum air temperatures and dew point temperature. The simulation results were analyzed using root mean square error (RMSE), Nash-Sutcliffe efficiency (NSE) coefficient, and violin plots. The results show that the copula-based model has high accuracy at all stations. The min (max) RMSE is related to Kerman (Ahvaz) station with RMSE = 0.396 oC (0.617 oC). Also, the min (max) NSE is related to Ahvaz (Urmia) station with NSE = 0.925 (0.955). Also, according to the violin plot, it is possible to appreciate the acceptable certainty of the copula-based model. Due to the diversity of the tree sequences of vine copulas and the use of the rotated states of the internal vine copulas, as well as the possibility of interfering with the effective parameters in high dimensions, the simulation results are reliable and have no restrictions. This model can be used as the best model to estimate dew point temperature due to the full coverage of the range of changes in data.
{"title":"Application of vine copulas to estimate dew point temperature","authors":"Yousef Ramezani, Mohammad Nazeri Tahroudi, Matina Pronoos Sedighi","doi":"10.20937/atm.53197","DOIUrl":"https://doi.org/10.20937/atm.53197","url":null,"abstract":"In this study, the accuracy of the copula-based model in the simulation of the dew point temperature in various climates of Iran was investigated, using simulations based on vine copulas such as C-, D-, and R-vine copulas. By examining the various vine copulas and their tree sequences, the best copula and best tree sequence based on AIC, BIC, and log-likelihood were selected. The results show that based on the complete similarity in our case between C-, D- and R-vine copulas, the selected best C-vine copulas fit well the dependence between the minimum and maximum air temperatures and dew point temperature. The simulation results were analyzed using root mean square error (RMSE), Nash-Sutcliffe efficiency (NSE) coefficient, and violin plots. The results show that the copula-based model has high accuracy at all stations. The min (max) RMSE is related to Kerman (Ahvaz) station with RMSE = 0.396 oC (0.617 oC). Also, the min (max) NSE is related to Ahvaz (Urmia) station with NSE = 0.925 (0.955). Also, according to the violin plot, it is possible to appreciate the acceptable certainty of the copula-based model. Due to the diversity of the tree sequences of vine copulas and the use of the rotated states of the internal vine copulas, as well as the possibility of interfering with the effective parameters in high dimensions, the simulation results are reliable and have no restrictions. This model can be used as the best model to estimate dew point temperature due to the full coverage of the range of changes in data.","PeriodicalId":55576,"journal":{"name":"Atmosfera","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135657264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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