T. Greenwald, R. Bennartz, C. O’Dell, A. Heidinger
Abstract Fast and accurate radiative transfer (RT) models are crucial in making use of microwave satellite data feasible under all weather conditions in numerical weather prediction (NWP) data assimilation. A multistream “successive order of scattering” (SOS) RT model has been developed to determine its suitability in NWP for computing microwave radiances in precipitating clouds. Results show that the two-stream SOS model is up to 10 times as fast as and is as accurate as the commonly used delta-Eddington model for weaker scattering [column scattering optical depth (CSOD) 30 GHz) in cases of moderately strong to strong scattering (CSOD > 5). If two- and four-stream SOS models are used in combination, however, it was found that 85.5-GHz brightness temperatures computed for 1° × 1° global forecast fields were more accurate ( 0.1) and were executed 4 times as fast as the delta-Eddington model. The SOS method has...
{"title":"Fast Computation of Microwave Radiances for Data Assimilation Using the “Successive Order of Scattering” Method.","authors":"T. Greenwald, R. Bennartz, C. O’Dell, A. Heidinger","doi":"10.1175/JAM2239.1","DOIUrl":"https://doi.org/10.1175/JAM2239.1","url":null,"abstract":"Abstract Fast and accurate radiative transfer (RT) models are crucial in making use of microwave satellite data feasible under all weather conditions in numerical weather prediction (NWP) data assimilation. A multistream “successive order of scattering” (SOS) RT model has been developed to determine its suitability in NWP for computing microwave radiances in precipitating clouds. Results show that the two-stream SOS model is up to 10 times as fast as and is as accurate as the commonly used delta-Eddington model for weaker scattering [column scattering optical depth (CSOD) 30 GHz) in cases of moderately strong to strong scattering (CSOD > 5). If two- and four-stream SOS models are used in combination, however, it was found that 85.5-GHz brightness temperatures computed for 1° × 1° global forecast fields were more accurate ( 0.1) and were executed 4 times as fast as the delta-Eddington model. The SOS method has...","PeriodicalId":15026,"journal":{"name":"Journal of Applied Meteorology","volume":"30 1","pages":"960-966"},"PeriodicalIF":0.0,"publicationDate":"2005-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84430159","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}
Abstract Relationships among convective planetary boundary layer (PBL) evolution and land surface properties are explored using data from the Atmospheric Radiation Measurement Program Cloud and Radiation Test Bed in the southern Great Plains. Previous attempts to infer surface fluxes from observations of the PBL have been constrained by difficulties in accurately estimating and parameterizing the conservation equation and have been limited to multiday averages or small samples of daily case studies. Using radiosonde and surface flux data for June, July, and August of 1997, 1999, and 2001, a conservation approach was applied to 132 sets of daily observations. Results highlight the limitations of using this method on daily time scales caused by the diurnal variability and complexity of entrainment. A statistical investigation of the relationship among PBL and both land surface and near-surface properties that are not explicitly included in conservation methods indicates that atmospheric stability in the lay...
{"title":"An Empirical Investigation of Convective Planetary Boundary Layer Evolution and Its Relationship with the Land Surface","authors":"J. Santanello, M. Friedl, W. Kustas","doi":"10.1175/JAM2240.1","DOIUrl":"https://doi.org/10.1175/JAM2240.1","url":null,"abstract":"Abstract Relationships among convective planetary boundary layer (PBL) evolution and land surface properties are explored using data from the Atmospheric Radiation Measurement Program Cloud and Radiation Test Bed in the southern Great Plains. Previous attempts to infer surface fluxes from observations of the PBL have been constrained by difficulties in accurately estimating and parameterizing the conservation equation and have been limited to multiday averages or small samples of daily case studies. Using radiosonde and surface flux data for June, July, and August of 1997, 1999, and 2001, a conservation approach was applied to 132 sets of daily observations. Results highlight the limitations of using this method on daily time scales caused by the diurnal variability and complexity of entrainment. A statistical investigation of the relationship among PBL and both land surface and near-surface properties that are not explicitly included in conservation methods indicates that atmospheric stability in the lay...","PeriodicalId":15026,"journal":{"name":"Journal of Applied Meteorology","volume":"36 1","pages":"917-932"},"PeriodicalIF":0.0,"publicationDate":"2005-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83904960","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}
Abstract Three multispectral algorithms for determining the cloud type of previously identified cloudy pixels during the daytime, using satellite imager data, are presented. Two algorithms were developed for use with 0.65-, 1.6-/3.75-, 10.8-, and 12.0-μm data from the Advanced Very High Resolution Radiometer (AVHRR) on board the National Oceanic and Atmospheric Administration (NOAA) operational polar-orbiting satellites. The AVHRR algorithms are identical except for the near-infrared data that are used. One algorithm uses AVHRR channel 3a (1.6 μm) reflectances, and the other uses AVHRR channel 3b (3.75 μm) reflectance estimates. Both of these algorithms are necessary because the AVHRRs on NOAA-15 through NOAA-17 have the capability to transmit either channel 3a or 3b data during the day, whereas all of the other AVHRRs on NOAA-7 through NOAA-14 can only transmit channel 3b data. The two AVHRR cloud-typing schemes are used operationally in NOAA’s extended Clouds from AVHRR (CLAVR)-x processing system. The ...
{"title":"Daytime Global Cloud Typing from AVHRR and VIIRS: Algorithm Description, Validation, and Comparisons","authors":"M. Pavolonis, A. Heidinger, T. Uttal","doi":"10.1175/JAM2236.1","DOIUrl":"https://doi.org/10.1175/JAM2236.1","url":null,"abstract":"Abstract Three multispectral algorithms for determining the cloud type of previously identified cloudy pixels during the daytime, using satellite imager data, are presented. Two algorithms were developed for use with 0.65-, 1.6-/3.75-, 10.8-, and 12.0-μm data from the Advanced Very High Resolution Radiometer (AVHRR) on board the National Oceanic and Atmospheric Administration (NOAA) operational polar-orbiting satellites. The AVHRR algorithms are identical except for the near-infrared data that are used. One algorithm uses AVHRR channel 3a (1.6 μm) reflectances, and the other uses AVHRR channel 3b (3.75 μm) reflectance estimates. Both of these algorithms are necessary because the AVHRRs on NOAA-15 through NOAA-17 have the capability to transmit either channel 3a or 3b data during the day, whereas all of the other AVHRRs on NOAA-7 through NOAA-14 can only transmit channel 3b data. The two AVHRR cloud-typing schemes are used operationally in NOAA’s extended Clouds from AVHRR (CLAVR)-x processing system. The ...","PeriodicalId":15026,"journal":{"name":"Journal of Applied Meteorology","volume":"79 1","pages":"804-826"},"PeriodicalIF":0.0,"publicationDate":"2005-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83927455","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}
Abstract Airborne in situ measurements of updrafts in tropical convective storms were analyzed to determine the similarities and differences between updrafts in a tropical continental and a tropical oceanic region. Two hundred fifteen updraft cores from the Tropical Rainfall Measuring Mission (TRMM) component of the Large Scale Biosphere–Atmosphere (LBA) experiment (tropical continental wet season) and 377 updraft cores from the Kwajalein Experiment (KWAJEX) (tropical oceanic) were analyzed in a similar manner to that of previous studies of tropical updrafts. Average speed, maximum speed, width, and mass flux of the updraft cores from the TRMM-LBA and KWAJEX were generally similar to each other and also were similar to results from previous studies of tropical updrafts.
{"title":"Characteristics of Strong Updrafts in Precipitation Systems over the Central Tropical Pacific Ocean and in the Amazon","authors":"Nicholas F. Anderson, C. A. Grainger, J. Stith","doi":"10.1175/JAM2231.1","DOIUrl":"https://doi.org/10.1175/JAM2231.1","url":null,"abstract":"Abstract Airborne in situ measurements of updrafts in tropical convective storms were analyzed to determine the similarities and differences between updrafts in a tropical continental and a tropical oceanic region. Two hundred fifteen updraft cores from the Tropical Rainfall Measuring Mission (TRMM) component of the Large Scale Biosphere–Atmosphere (LBA) experiment (tropical continental wet season) and 377 updraft cores from the Kwajalein Experiment (KWAJEX) (tropical oceanic) were analyzed in a similar manner to that of previous studies of tropical updrafts. Average speed, maximum speed, width, and mass flux of the updraft cores from the TRMM-LBA and KWAJEX were generally similar to each other and also were similar to results from previous studies of tropical updrafts.","PeriodicalId":15026,"journal":{"name":"Journal of Applied Meteorology","volume":"43 1","pages":"731-738"},"PeriodicalIF":0.0,"publicationDate":"2005-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74186496","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}
B. Mendoza, E. Jáuregui, R. Díaz-Sandoval, Virginia García‐Acosta, V. Velasco, Guadalupe Cordero
A catalog containing an unprecedented amount of historical data in central Mexico, covering almost six centuries (1450–1900), is used. This is a catalog of agricultural disasters that includes events associated with hydrometeorological phenomena, or hazards, whose effects were mainly felt in the agricultural sector, such as droughts. An analysis of the historical series of droughts in central Mexico for the period of 1450–1900 is performed. Periods of frequent drought centered at the years 1483, 1533, 1571, 1601, 1650, 1691, 1730, 1783, 1818, and 1860 have been identified. In particular, droughts in Mexico City and northwest Mexico that were identified through poor tree-ring growth are included in the frequent drought periods obtained in this work. Moreover, it was found that droughts occurred in El Nino years mainly for events of very strong and strong strengths, at a significant level. Also, most droughts lasted for 1 or 2 yr. Last, by analyzing the periodicities of the drought time series it was found that those that are the most conspicuous are the quasi-bidecadal frequencies of 18.9 and 21 yr.
{"title":"Historical Droughts in Central Mexico and Their Relation with El Niño","authors":"B. Mendoza, E. Jáuregui, R. Díaz-Sandoval, Virginia García‐Acosta, V. Velasco, Guadalupe Cordero","doi":"10.1175/JAM2210.1","DOIUrl":"https://doi.org/10.1175/JAM2210.1","url":null,"abstract":"A catalog containing an unprecedented amount of historical data in central Mexico, covering almost six centuries (1450–1900), is used. This is a catalog of agricultural disasters that includes events associated with hydrometeorological phenomena, or hazards, whose effects were mainly felt in the agricultural sector, such as droughts. An analysis of the historical series of droughts in central Mexico for the period of 1450–1900 is performed. Periods of frequent drought centered at the years 1483, 1533, 1571, 1601, 1650, 1691, 1730, 1783, 1818, and 1860 have been identified. In particular, droughts in Mexico City and northwest Mexico that were identified through poor tree-ring growth are included in the frequent drought periods obtained in this work. Moreover, it was found that droughts occurred in El Nino years mainly for events of very strong and strong strengths, at a significant level. Also, most droughts lasted for 1 or 2 yr. Last, by analyzing the periodicities of the drought time series it was found that those that are the most conspicuous are the quasi-bidecadal frequencies of 18.9 and 21 yr.","PeriodicalId":15026,"journal":{"name":"Journal of Applied Meteorology","volume":"25 1","pages":"709-716"},"PeriodicalIF":0.0,"publicationDate":"2005-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91532878","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}
Through modification of the planetary boundary layer, urbanization has the potential to have a significant impact on precipitation totals locally. Using daily summer-season precipitation data at 30 stations from 1953 to 2002, this study explores the possibility of urban effects as causes of spatial anomalies in precipitation in a zone within 180 km of Atlanta, Georgia. The time period is divided into consecutive epochs (e.g., 1953–77 and 1978–2002), and interepochal differences in precipitation totals, heavy-precipitation days, cumulative heavy precipitation, and atmospheric conditions are explored. The southern stations experienced significant decreases in precipitation, whereas significant precipitation increases occurred at central/west-central stations. The most striking increases occurred at Norcross, Georgia, which is 30 km northeast of downtown Atlanta; Norcross had the third smallest number of heavy-precipitation days during 1953–77, but, during 1978–2002, it had the most heavy-precipitation days. Not only did the amount of urban land cover upwind of Norcross increase substantially from the earlier to the later epochs, but regionwide dewpoint temperatures also increased significantly. Therefore, it is suspected that the increased precipitation at Norcross was caused by urban effects, and these effects may have been enhanced by increased atmospheric humidity.
{"title":"Interepochal Changes in Summer Precipitation in the Southeastern United States: Evidence of Possible Urban Effects near Atlanta, Georgia","authors":"J. Diem, T. Mote","doi":"10.1175/JAM2221.1","DOIUrl":"https://doi.org/10.1175/JAM2221.1","url":null,"abstract":"Through modification of the planetary boundary layer, urbanization has the potential to have a significant impact on precipitation totals locally. Using daily summer-season precipitation data at 30 stations from 1953 to 2002, this study explores the possibility of urban effects as causes of spatial anomalies in precipitation in a zone within 180 km of Atlanta, Georgia. The time period is divided into consecutive epochs (e.g., 1953–77 and 1978–2002), and interepochal differences in precipitation totals, heavy-precipitation days, cumulative heavy precipitation, and atmospheric conditions are explored. The southern stations experienced significant decreases in precipitation, whereas significant precipitation increases occurred at central/west-central stations. The most striking increases occurred at Norcross, Georgia, which is 30 km northeast of downtown Atlanta; Norcross had the third smallest number of heavy-precipitation days during 1953–77, but, during 1978–2002, it had the most heavy-precipitation days. Not only did the amount of urban land cover upwind of Norcross increase substantially from the earlier to the later epochs, but regionwide dewpoint temperatures also increased significantly. Therefore, it is suspected that the increased precipitation at Norcross was caused by urban effects, and these effects may have been enhanced by increased atmospheric humidity.","PeriodicalId":15026,"journal":{"name":"Journal of Applied Meteorology","volume":"14 20 1","pages":"717-730"},"PeriodicalIF":0.0,"publicationDate":"2005-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80671545","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}
S. Perry, A. Cimorelli, R. Paine, R. Brode, J. Weil, A. Venkatram, R. Wilson, Russell F. Lee, W. Peters
Abstract The performance of the American Meteorological Society (AMS) and U.S. Environmental Protection Agency (EPA) Regulatory Model (AERMOD) Improvement Committee’s applied air dispersion model against 17 field study databases is described. AERMOD is a steady-state plume model with significant improvements over commonly applied regulatory models. The databases are characterized, and the performance measures are described. Emphasis is placed on statistics that demonstrate the model’s abilities to reproduce the upper end of the concentration distribution. This is most important for applied regulatory modeling. The field measurements are characterized by flat and complex terrain, urban and rural conditions, and elevated and surface releases with and without building wake effects. As is indicated by comparisons of modeled and observed concentration distributions, with few exceptions AERMOD’s performance is superior to that of the other applied models tested. This is the second of two articles, with the firs...
{"title":"AERMOD: A dispersion model for industrial source applications. Part II: Model performance against 17 field study databases","authors":"S. Perry, A. Cimorelli, R. Paine, R. Brode, J. Weil, A. Venkatram, R. Wilson, Russell F. Lee, W. Peters","doi":"10.1175/JAM2228.1","DOIUrl":"https://doi.org/10.1175/JAM2228.1","url":null,"abstract":"Abstract The performance of the American Meteorological Society (AMS) and U.S. Environmental Protection Agency (EPA) Regulatory Model (AERMOD) Improvement Committee’s applied air dispersion model against 17 field study databases is described. AERMOD is a steady-state plume model with significant improvements over commonly applied regulatory models. The databases are characterized, and the performance measures are described. Emphasis is placed on statistics that demonstrate the model’s abilities to reproduce the upper end of the concentration distribution. This is most important for applied regulatory modeling. The field measurements are characterized by flat and complex terrain, urban and rural conditions, and elevated and surface releases with and without building wake effects. As is indicated by comparisons of modeled and observed concentration distributions, with few exceptions AERMOD’s performance is superior to that of the other applied models tested. This is the second of two articles, with the firs...","PeriodicalId":15026,"journal":{"name":"Journal of Applied Meteorology","volume":"20 1","pages":"694-708"},"PeriodicalIF":0.0,"publicationDate":"2005-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88060192","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}
A. Cimorelli, S. Perry, A. Venkatram, J. Weil, R. Paine, R. Wilson, Russell F. Lee, W. Peters, R. Brode
Abstract The formulation of the American Meteorological Society (AMS) and U.S. Environmental Protection Agency (EPA) Regulatory Model (AERMOD) Improvement Committee’s applied air dispersion model is described. This is the first of two articles describing the model and its performance. Part I includes AERMOD’s characterization of the boundary layer with computation of the Monin–Obukhov length, surface friction velocity, surface roughness length, sensible heat flux, convective scaling velocity, and both the shear- and convection-driven mixing heights. These parameters are used in conjunction with meteorological measurements to characterize the vertical structure of the wind, temperature, and turbulence. AERMOD’s method for considering both the vertical inhomogeneity of the meteorological characteristics and the influence of terrain are explained. The model’s concentration estimates are based on a steady-state plume approach with significant improvements over commonly applied regulatory dispersion models. Co...
{"title":"AERMOD: A Dispersion Model for Industrial Source Applications. Part I: General Model Formulation and Boundary Layer Characterization.","authors":"A. Cimorelli, S. Perry, A. Venkatram, J. Weil, R. Paine, R. Wilson, Russell F. Lee, W. Peters, R. Brode","doi":"10.1175/JAM2227.1","DOIUrl":"https://doi.org/10.1175/JAM2227.1","url":null,"abstract":"Abstract The formulation of the American Meteorological Society (AMS) and U.S. Environmental Protection Agency (EPA) Regulatory Model (AERMOD) Improvement Committee’s applied air dispersion model is described. This is the first of two articles describing the model and its performance. Part I includes AERMOD’s characterization of the boundary layer with computation of the Monin–Obukhov length, surface friction velocity, surface roughness length, sensible heat flux, convective scaling velocity, and both the shear- and convection-driven mixing heights. These parameters are used in conjunction with meteorological measurements to characterize the vertical structure of the wind, temperature, and turbulence. AERMOD’s method for considering both the vertical inhomogeneity of the meteorological characteristics and the influence of terrain are explained. The model’s concentration estimates are based on a steady-state plume approach with significant improvements over commonly applied regulatory dispersion models. Co...","PeriodicalId":15026,"journal":{"name":"Journal of Applied Meteorology","volume":"52 1","pages":"682-693"},"PeriodicalIF":0.0,"publicationDate":"2005-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88420687","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}
Abstract A 3-yr dataset (February 2000–November 2002) of 30-min averages for particulates, visibility, and meteorological data were analyzed to examine the dependence of particulate matter of less than 10 μm in diameter (PM10) mass concentrations and visibility in Tel Aviv, Israel, on seasonal meteorological conditions, synoptic weather patterns, and airmass history. The persistent nature of the summer synoptic weather pattern in the east Mediterranean (EM) region yielded the highest mean visibility (35 km) and lowest variability in PM10 concentrations, as compared with the higher variance for the other seasons, and spring in particular. The frequent passage of the “Sharav” cyclones during spring causes natural dust outbreaks with extreme values that result in a much higher PM10 annual mean (57 μg m−3) as compared with other larger cities. The history of the air mass dictating the physical and chemical properties of the particulate matter reaching Israel was assessed by back-trajectory analysis from prede...
摘要利用2000年2月至2002年11月的3年颗粒物、能见度和气象数据集，分析了以色列特拉维夫地区直径小于10 μm的颗粒物(PM10)质量浓度和能见度与季节气象条件、天气模式和气团历史的关系。东地中海(EM)地区夏季天气型的持续性产生了最高的平均能见度(35公里)和最低的PM10浓度变异，而其他季节，特别是春季的变异较大。春季频繁经过的“Sharav”气旋导致自然沙尘爆发，其极端值导致PM10年平均值(57 μg m - 3)比其他大城市高得多。空气团的历史决定了到达以色列的颗粒物质的物理和化学性质，这是通过从prede…
{"title":"The influence of meteorological conditions and atmospheric circulation types on PM10 and visibility in Tel Aviv","authors":"U. Dayan, Ilan Levy","doi":"10.1175/JAM2232.1","DOIUrl":"https://doi.org/10.1175/JAM2232.1","url":null,"abstract":"Abstract A 3-yr dataset (February 2000–November 2002) of 30-min averages for particulates, visibility, and meteorological data were analyzed to examine the dependence of particulate matter of less than 10 μm in diameter (PM10) mass concentrations and visibility in Tel Aviv, Israel, on seasonal meteorological conditions, synoptic weather patterns, and airmass history. The persistent nature of the summer synoptic weather pattern in the east Mediterranean (EM) region yielded the highest mean visibility (35 km) and lowest variability in PM10 concentrations, as compared with the higher variance for the other seasons, and spring in particular. The frequent passage of the “Sharav” cyclones during spring causes natural dust outbreaks with extreme values that result in a much higher PM10 annual mean (57 μg m−3) as compared with other larger cities. The history of the air mass dictating the physical and chemical properties of the particulate matter reaching Israel was assessed by back-trajectory analysis from prede...","PeriodicalId":15026,"journal":{"name":"Journal of Applied Meteorology","volume":"76 1","pages":"606-619"},"PeriodicalIF":0.0,"publicationDate":"2005-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81108512","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}
M. D. Schultz, S. Underwood, Premkrishnan Radhakrishnan
Abstract Currently, no uniform method exists for determining the optimal areal unit to analyze National Lightning Detection Network (NLDN) data. To address this problem, this paper utilizes the capabilities of modern geographic information systems (GIS) software to develop a consistent method for identifying areal analysis units while considering the location accuracy of the NLDN. Five grid cells were created at spatial resolutions of 0.1°, 0.2°, 0.3°, 0.4°, and 0.5°. To create cloud-to-ground (CG) lightning strikes, random points were generated at nine densities ranging from 1 to 9 strikes per square kilometer. A buffer of 500 m was placed around each random point to account for the margin of error in NLDN location accuracy. Random points that, when buffered to 500 m, still remained completely within the study region were evaluated as a percentage of all of the strikes to determine accuracy. The greatest accuracy of 95.88% was observed in the 0.5° grid cell at a density of 9 strikes per square kilometer....
{"title":"A Method to Identify the Optimal Areal Unit for NLDN Cloud-to-Ground Lightning Flash Data Analysis.","authors":"M. D. Schultz, S. Underwood, Premkrishnan Radhakrishnan","doi":"10.1175/JAM2234.1","DOIUrl":"https://doi.org/10.1175/JAM2234.1","url":null,"abstract":"Abstract Currently, no uniform method exists for determining the optimal areal unit to analyze National Lightning Detection Network (NLDN) data. To address this problem, this paper utilizes the capabilities of modern geographic information systems (GIS) software to develop a consistent method for identifying areal analysis units while considering the location accuracy of the NLDN. Five grid cells were created at spatial resolutions of 0.1°, 0.2°, 0.3°, 0.4°, and 0.5°. To create cloud-to-ground (CG) lightning strikes, random points were generated at nine densities ranging from 1 to 9 strikes per square kilometer. A buffer of 500 m was placed around each random point to account for the margin of error in NLDN location accuracy. Random points that, when buffered to 500 m, still remained completely within the study region were evaluated as a percentage of all of the strikes to determine accuracy. The greatest accuracy of 95.88% was observed in the 0.5° grid cell at a density of 9 strikes per square kilometer....","PeriodicalId":15026,"journal":{"name":"Journal of Applied Meteorology","volume":"101 1","pages":"739-744"},"PeriodicalIF":0.0,"publicationDate":"2005-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86956566","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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