Pub Date : 2023-08-09DOI: 10.1175/jamc-d-22-0108.1
Athanasios Ntoumos, P. Hadjinicolaou, G. Zittis, Katiana Constantinidou, Anna Tzyrkalli, J. Lelieveld
We assess the sensitivity of the Weather Research and Forecast (WRF) model to the use of different planetary boundary layer (PBL) parameterizations focusing on air temperature and extreme heat conditions. This work aims to evaluate the performance of the WRF model in simulating temperatures across the Middle-East - North Africa (MENA) domain, explain the model biases resulting from the choice of different PBL schemes, and identify the best performing configuration for the MENA region. Three different PBL schemes are used to downscale the ECMWF ERA-Interim climate over the MENA region at a horizontal resolution of 24 km, for the period 2000–2010. These are the Mellor–Yamada–Janjic (MYJ), Yonsei University (YSU) and the Asymmetric Convective Model, version 2 (ACM2). For the evaluation of the WRF runs we used related meteorological variables from the ERA5 reanalysis including summer maximum and minimum 2-meter air temperature and heat extreme indices. Our results indicate that simulations tend to overestimate maximum and underestimate minimum temperatures, while we find that model errors are very dependent on the geographic location. The possible physical causes of model biases are investigated through the analysis of additional variables (such as boundary layer height, moisture and heat fluxes). It is shown that differences among the PBL schemes are associated with differences in vertical mixing strength which alters the magnitude of the entrainment of free-tropospheric air into the PBL. The YSU is found to be the best performing scheme and it is recommended in WRF climate simulations for the MENA region.
{"title":"Evaluation of WRF model boundary layer schemes in simulating temperature and heat extremes over the Middle-East – North Africa (MENA) region","authors":"Athanasios Ntoumos, P. Hadjinicolaou, G. Zittis, Katiana Constantinidou, Anna Tzyrkalli, J. Lelieveld","doi":"10.1175/jamc-d-22-0108.1","DOIUrl":"https://doi.org/10.1175/jamc-d-22-0108.1","url":null,"abstract":"\u0000We assess the sensitivity of the Weather Research and Forecast (WRF) model to the use of different planetary boundary layer (PBL) parameterizations focusing on air temperature and extreme heat conditions. This work aims to evaluate the performance of the WRF model in simulating temperatures across the Middle-East - North Africa (MENA) domain, explain the model biases resulting from the choice of different PBL schemes, and identify the best performing configuration for the MENA region. Three different PBL schemes are used to downscale the ECMWF ERA-Interim climate over the MENA region at a horizontal resolution of 24 km, for the period 2000–2010. These are the Mellor–Yamada–Janjic (MYJ), Yonsei University (YSU) and the Asymmetric Convective Model, version 2 (ACM2). For the evaluation of the WRF runs we used related meteorological variables from the ERA5 reanalysis including summer maximum and minimum 2-meter air temperature and heat extreme indices. Our results indicate that simulations tend to overestimate maximum and underestimate minimum temperatures, while we find that model errors are very dependent on the geographic location. The possible physical causes of model biases are investigated through the analysis of additional variables (such as boundary layer height, moisture and heat fluxes). It is shown that differences among the PBL schemes are associated with differences in vertical mixing strength which alters the magnitude of the entrainment of free-tropospheric air into the PBL. The YSU is found to be the best performing scheme and it is recommended in WRF climate simulations for the MENA region.","PeriodicalId":15027,"journal":{"name":"Journal of Applied Meteorology and Climatology","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46672650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-09DOI: 10.1175/jamc-d-22-0201.1
Z.J. Zuo, J. Fung, Zhenning Li, Yiyi Huang, Mau Fung Wong, A. Lau, Xingcheng Lu
Recent worldwide heatwaves have shattered temperature records in many regions. In this study, we applied a dynamical downscaling method on the high-resolution version of the Max Planck Institute Earth System Model (MPI-ESM-1-2-HR) to obtain projections of the summer thermal environments and heatwaves in the Pearl River Delta (PRD) considering three shared socioeconomic pathways (SSP1-2.6, SSP2-4.5, and SSP5-8.5) in the middle and late 21st century. Results indicated that relative to the temperatures in the 2010s, the mean increases in the summer (June–September) daytime and nighttime temperatures in the 2040s will be 0.7– 0.8 °C and 0.9–1.1 °C, respectively. In the 2090s, the mean difference will be 0.5–3.1 °C and 0.7–3.4 °C, respectively. SSP1-2.6 is the only scenario in which the temperatures in the 2090s are expected to be lower than those in the 2040s. Compared with those in the 2010s, hot extremes are expected to be more frequent, intense, extensive, and longer-lasting in the future in the SSP2-4.5 and SSP5-8.5 scenarios. In the 2010s, a heatwave occurred in the PRD lasted for 6 days on average, with a mean daily maximum temperature of 34.4 °C. In the 2040s, the heatwave duration and intensity are expected to increase by 2–3 days and 0.2–0.4 °C in all three scenarios. In the 2090s, the increase in these values will be 23 days and 36.0 °C in SSP5-8.5. Moreover, a 10-year extreme high temperature in the 2010s is expected to occur at a monthly frequency from June to September in the 2090s.
{"title":"Projection of future heatwaves in the Pearl River Delta through CMIP6-WRF dynamical downscaling","authors":"Z.J. Zuo, J. Fung, Zhenning Li, Yiyi Huang, Mau Fung Wong, A. Lau, Xingcheng Lu","doi":"10.1175/jamc-d-22-0201.1","DOIUrl":"https://doi.org/10.1175/jamc-d-22-0201.1","url":null,"abstract":"\u0000Recent worldwide heatwaves have shattered temperature records in many regions. In this study, we applied a dynamical downscaling method on the high-resolution version of the Max Planck Institute Earth System Model (MPI-ESM-1-2-HR) to obtain projections of the summer thermal environments and heatwaves in the Pearl River Delta (PRD) considering three shared socioeconomic pathways (SSP1-2.6, SSP2-4.5, and SSP5-8.5) in the middle and late 21st century. Results indicated that relative to the temperatures in the 2010s, the mean increases in the summer (June–September) daytime and nighttime temperatures in the 2040s will be 0.7– 0.8 °C and 0.9–1.1 °C, respectively. In the 2090s, the mean difference will be 0.5–3.1 °C and 0.7–3.4 °C, respectively. SSP1-2.6 is the only scenario in which the temperatures in the 2090s are expected to be lower than those in the 2040s. Compared with those in the 2010s, hot extremes are expected to be more frequent, intense, extensive, and longer-lasting in the future in the SSP2-4.5 and SSP5-8.5 scenarios. In the 2010s, a heatwave occurred in the PRD lasted for 6 days on average, with a mean daily maximum temperature of 34.4 °C. In the 2040s, the heatwave duration and intensity are expected to increase by 2–3 days and 0.2–0.4 °C in all three scenarios. In the 2090s, the increase in these values will be 23 days and 36.0 °C in SSP5-8.5. Moreover, a 10-year extreme high temperature in the 2010s is expected to occur at a monthly frequency from June to September in the 2090s.","PeriodicalId":15027,"journal":{"name":"Journal of Applied Meteorology and Climatology","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43671830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-08DOI: 10.1175/jamc-d-23-0026.1
W. J. Steenburgh, Julie A. Cunningham, Philip T. Bergmaier, B. Geerts, Peter G. Veals
Potential factors affecting the inland penetration and orographic modulation of lake-effect precipitation east of Lake Ontario include the environmental (lake, land, and atmospheric) conditions, mode of the lake-effect system, and orographic processes associated with flow across the downstream Tug Hill Plateau (hereafter Tug Hill), Black River Valley, and Adirondack Mountains (hereafter Adirondacks). In this study we use data from the KTYX WSR-88D, ERA5 reanalysis, New York State Mesonet, and Ontario Winter Lake-effect Systems (OWLeS) field campaign to examine how these factors influence lake-effect characteristics with emphasis on the region downstream of Tug Hill. During an eight cool season (16 November – 15 April) study period (2012/13–2019/20), total radar-estimated precipitation during lake-effect periods increased gradually from Lake Ontario to upper Tug Hill and decreased abruptly where the Tug Hill escarpment drops into the Black River Valley. The axis of maximum precipitation shifted poleward across the northern Black River Valley and into the northwestern Adirondacks. In the western Adirondacks, the heaviest lake-effect snowfall periods featured strong, near-zonal boundary layer flow, a deep boundary layer, and a single precipitation band aligned along the long-lake axis. Airborne profiling radar observations collected during OWLeS IOP10 revealed precipitation enhancement over Tug Hill, spillover and shadowing in the Black River Valley where a resonant lee wave was present, and precipitation invigoration over the western Adirondacks. These results illustrate the orographic modulation of inland-penetrating lake-effect systems downstream of Lake Ontario and the factors favoring heavy snowfall over the western Adirondacks.
{"title":"Characteristics of Lake-Effect Precipitation over the Black River Valley and Western Adirondack Mountains","authors":"W. J. Steenburgh, Julie A. Cunningham, Philip T. Bergmaier, B. Geerts, Peter G. Veals","doi":"10.1175/jamc-d-23-0026.1","DOIUrl":"https://doi.org/10.1175/jamc-d-23-0026.1","url":null,"abstract":"\u0000Potential factors affecting the inland penetration and orographic modulation of lake-effect precipitation east of Lake Ontario include the environmental (lake, land, and atmospheric) conditions, mode of the lake-effect system, and orographic processes associated with flow across the downstream Tug Hill Plateau (hereafter Tug Hill), Black River Valley, and Adirondack Mountains (hereafter Adirondacks). In this study we use data from the KTYX WSR-88D, ERA5 reanalysis, New York State Mesonet, and Ontario Winter Lake-effect Systems (OWLeS) field campaign to examine how these factors influence lake-effect characteristics with emphasis on the region downstream of Tug Hill.\u0000During an eight cool season (16 November – 15 April) study period (2012/13–2019/20), total radar-estimated precipitation during lake-effect periods increased gradually from Lake Ontario to upper Tug Hill and decreased abruptly where the Tug Hill escarpment drops into the Black River Valley. The axis of maximum precipitation shifted poleward across the northern Black River Valley and into the northwestern Adirondacks. In the western Adirondacks, the heaviest lake-effect snowfall periods featured strong, near-zonal boundary layer flow, a deep boundary layer, and a single precipitation band aligned along the long-lake axis. Airborne profiling radar observations collected during OWLeS IOP10 revealed precipitation enhancement over Tug Hill, spillover and shadowing in the Black River Valley where a resonant lee wave was present, and precipitation invigoration over the western Adirondacks. These results illustrate the orographic modulation of inland-penetrating lake-effect systems downstream of Lake Ontario and the factors favoring heavy snowfall over the western Adirondacks.","PeriodicalId":15027,"journal":{"name":"Journal of Applied Meteorology and Climatology","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46957575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-04DOI: 10.1175/jamc-d-22-0153.1
F. Fabry, Joseph Samuel, V. Meunier
In a future world where most of the energy must come from intermittent renewable energy sources such as wind or solar energy, it would be more efficient if, for each demand area, we could determine the locations for which the output of an energy source would naturally match the demand fluctuations from that area. In parallel, meteorological weather systems such as midlatitude cyclones are often organized in a way that naturally shapes where areas of greater energy need (say, regions with more cold air) are with respect to windier or sunnier areas, and these are generally not collocated. As a result, the best places to generate renewable energy may not be near consumption sites; these may however be determined by common meteorological patterns. Using data from a reanalysis of six decades of past weather, we determined the complementarity between different sources of energy as well as the relationships between renewable supply and demand at daily-averaged time scales for several North American cities. In general, demand and solar power tend to be slightly positively correlated at nearby locations away from the Rockies; however, wind power often must be obtained from greater distances and at altitude for energy production to be better timed with consumption.
{"title":"Weather Driven Complementarity Between Daily Energy Demand at One Location and Renewable Supply at Another","authors":"F. Fabry, Joseph Samuel, V. Meunier","doi":"10.1175/jamc-d-22-0153.1","DOIUrl":"https://doi.org/10.1175/jamc-d-22-0153.1","url":null,"abstract":"\u0000In a future world where most of the energy must come from intermittent renewable energy sources such as wind or solar energy, it would be more efficient if, for each demand area, we could determine the locations for which the output of an energy source would naturally match the demand fluctuations from that area. In parallel, meteorological weather systems such as midlatitude cyclones are often organized in a way that naturally shapes where areas of greater energy need (say, regions with more cold air) are with respect to windier or sunnier areas, and these are generally not collocated. As a result, the best places to generate renewable energy may not be near consumption sites; these may however be determined by common meteorological patterns. Using data from a reanalysis of six decades of past weather, we determined the complementarity between different sources of energy as well as the relationships between renewable supply and demand at daily-averaged time scales for several North American cities. In general, demand and solar power tend to be slightly positively correlated at nearby locations away from the Rockies; however, wind power often must be obtained from greater distances and at altitude for energy production to be better timed with consumption.","PeriodicalId":15027,"journal":{"name":"Journal of Applied Meteorology and Climatology","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2023-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49581775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-01DOI: 10.1175/jamc-d-22-0137.1
Jiang-ping Zhu, A. Xie, X. Qin, Shimeng Wang, Bingbo Xu, Yicheng Wang
Global warming has been accelerating the frequency and intensity of climate extremes, and has had an immense influence on the economy and society, but attention is seldom paid to future Antarctic temperature extremes. This study investigates five surface extreme temperature indices derived from the multimodel ensemble mean (MMEM) based on 14 models from phase 6 of the Coupled Model Intercomparison Project (CMIP6) under the shared socioeconomic pathways (SSPs) of SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5. In Antarctica, the variations in extreme temperature indices exhibit regional and seasonal differences. The diurnal temperature range (DTR) usually illustrates a downward trend, particularly for the Antarctic Peninsula and Antarctic coast, and the strongest change occurs in austral summer. In all cases, the annual highest minimum/maximum temperature (TNx/TXx) increases faster in inland Antarctica. Antarctic amplification of extreme temperature indices is detected and is strongest at the lowest maximum temperature (TXn). At the Antarctic Peninsula, TXx amplification only appears in winter. Great DTR amplification appears along the Antarctic coast and is strongest in summer and weakest in winter. The changes in extreme temperature indices indicate the accelerated Antarctic warming in future scenarios.
{"title":"Projection on Antarctic Temperature Extremes from the CMIP6 Multimodel Ensemble under Different Scenarios","authors":"Jiang-ping Zhu, A. Xie, X. Qin, Shimeng Wang, Bingbo Xu, Yicheng Wang","doi":"10.1175/jamc-d-22-0137.1","DOIUrl":"https://doi.org/10.1175/jamc-d-22-0137.1","url":null,"abstract":"\u0000Global warming has been accelerating the frequency and intensity of climate extremes, and has had an immense influence on the economy and society, but attention is seldom paid to future Antarctic temperature extremes. This study investigates five surface extreme temperature indices derived from the multimodel ensemble mean (MMEM) based on 14 models from phase 6 of the Coupled Model Intercomparison Project (CMIP6) under the shared socioeconomic pathways (SSPs) of SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5. In Antarctica, the variations in extreme temperature indices exhibit regional and seasonal differences. The diurnal temperature range (DTR) usually illustrates a downward trend, particularly for the Antarctic Peninsula and Antarctic coast, and the strongest change occurs in austral summer. In all cases, the annual highest minimum/maximum temperature (TNx/TXx) increases faster in inland Antarctica. Antarctic amplification of extreme temperature indices is detected and is strongest at the lowest maximum temperature (TXn). At the Antarctic Peninsula, TXx amplification only appears in winter. Great DTR amplification appears along the Antarctic coast and is strongest in summer and weakest in winter. The changes in extreme temperature indices indicate the accelerated Antarctic warming in future scenarios.","PeriodicalId":15027,"journal":{"name":"Journal of Applied Meteorology and Climatology","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45073794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-01DOI: 10.1175/jamc-628masthead
{"title":"Masthead","authors":"","doi":"10.1175/jamc-628masthead","DOIUrl":"https://doi.org/10.1175/jamc-628masthead","url":null,"abstract":"","PeriodicalId":15027,"journal":{"name":"Journal of Applied Meteorology and Climatology","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43796896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-31DOI: 10.1175/jamc-d-23-0029.1
Yen-Chao Chiu, F. Chien
This study investigates the characteristics and long-term trends of southwesterly flows around southern Taiwan (hereafter, SWs) during mei-yu seasons (15 May–15 June) from 1979 to 2022. The results show that the occurrence number of SWs in general exhibited an increasing trend over this 44-year period, with a decadal oscillation starting from a relatively small number in the 1980s and reaching a relative peak in the 2000s. This tendency posts a potential threat to Taiwan due to the increasing trend of heavy rainfall associated with higher moisture flux of the SWs events. The SWs activity was influenced by the long-term increasing trend of geopotential height gradients and their decadal variability near Taiwan. When the intra-seasonal oscillation was evident, the weather system mainly affecting the occurrence of SWs was the low pressure system to the north of Taiwan; when it was weak, the intensity and location of the western North Pacific subtropical high to the south of Taiwan was relatively more important. In addition, the SWs index which was highly correlated with the precipitation during mei-yu seasons can effectively reflect the interannual variability of precipitation in Taiwan in periods of different lengths. These findings indicate that the SWs index can be used as a monsoonal precipitation index for Taiwan, especially southern Taiwan.
{"title":"Long-term Trends and Interannual Variability of Southwesterly Flows around Southern Taiwan during 44 Mei-yu Seasons","authors":"Yen-Chao Chiu, F. Chien","doi":"10.1175/jamc-d-23-0029.1","DOIUrl":"https://doi.org/10.1175/jamc-d-23-0029.1","url":null,"abstract":"\u0000This study investigates the characteristics and long-term trends of southwesterly flows around southern Taiwan (hereafter, SWs) during mei-yu seasons (15 May–15 June) from 1979 to 2022. The results show that the occurrence number of SWs in general exhibited an increasing trend over this 44-year period, with a decadal oscillation starting from a relatively small number in the 1980s and reaching a relative peak in the 2000s. This tendency posts a potential threat to Taiwan due to the increasing trend of heavy rainfall associated with higher moisture flux of the SWs events. The SWs activity was influenced by the long-term increasing trend of geopotential height gradients and their decadal variability near Taiwan. When the intra-seasonal oscillation was evident, the weather system mainly affecting the occurrence of SWs was the low pressure system to the north of Taiwan; when it was weak, the intensity and location of the western North Pacific subtropical high to the south of Taiwan was relatively more important. In addition, the SWs index which was highly correlated with the precipitation during mei-yu seasons can effectively reflect the interannual variability of precipitation in Taiwan in periods of different lengths. These findings indicate that the SWs index can be used as a monsoonal precipitation index for Taiwan, especially southern Taiwan.","PeriodicalId":15027,"journal":{"name":"Journal of Applied Meteorology and Climatology","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46721628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-28DOI: 10.1175/jamc-d-21-0222.1
René Bodjrènou, J. Cohard, B. Hector, E. Lawin, G. Chagnaud, D. Danso, Yèkambèssoun N’Tcha M’Po, Félicien D. Badou, B. Ahamidé
In West Africa, climatic data issues, especially availability and quality, remain a significant constraint to the development and application of distributed hydrological modeling. As alternatives to ground-based observations, reanalysis products have received increasing attention in recent years. This study aims to evaluate three reanalysis products, namely, ERA5, WFDE5, and MERRA2, from 1981 to 2019 to determine their ability to represent four hydrological climates variables over a range of space and timescales in Benin. The variables from the reanalysis products are compared to point station data-based metrics Kling Gupta Efficiency (KGE), Mean Absolute Error (MAE), correlation, and Relative Error in Precipitation Annual (REPA). The results show that ERA5 presents a better correlation for annual mean temperature (between 0.74-0.90) compared to WFDE5 (0.63-0.78) and MERRA2 (0.25-0.65). Both ERA5 and WFDE5 are able to reproduce the observed upward trend of temperature (0.2°C/decade) in the region. We noted a systematic cold bias of ~1.3°C in all reanalyses except WFDE5 (~0.1°C). On the monthly timescale, the temperature of the region is better reproduced by ERA5 and WFDE5 (KGE ≥ 0.80) compared to MERRA2 (KGE < 0.5). At all timescales, WFDE5 produces the best MAE scores for longwave (LW) and shortwave (SW) radiation followed by ERA5. WFDE5 also provides the best estimates for the annual precipitation (REPA ∈ ]-25, 25[ and KGE ≥ 50% at most stations). ERA5 produces similar results, but MERRA2 performs poorly in all the metrics. Additionally, ERA5 and WFDE5 reproduce the bimodal rainfall regime in southern Benin, unlike MERRA2, but all products have too many small rainfall events.
{"title":"Evaluation of reanalysis estimates of precipitation, radiation and temperature over Benin (West Africa)","authors":"René Bodjrènou, J. Cohard, B. Hector, E. Lawin, G. Chagnaud, D. Danso, Yèkambèssoun N’Tcha M’Po, Félicien D. Badou, B. Ahamidé","doi":"10.1175/jamc-d-21-0222.1","DOIUrl":"https://doi.org/10.1175/jamc-d-21-0222.1","url":null,"abstract":"\u0000In West Africa, climatic data issues, especially availability and quality, remain a significant constraint to the development and application of distributed hydrological modeling. As alternatives to ground-based observations, reanalysis products have received increasing attention in recent years. This study aims to evaluate three reanalysis products, namely, ERA5, WFDE5, and MERRA2, from 1981 to 2019 to determine their ability to represent four hydrological climates variables over a range of space and timescales in Benin. The variables from the reanalysis products are compared to point station data-based metrics Kling Gupta Efficiency (KGE), Mean Absolute Error (MAE), correlation, and Relative Error in Precipitation Annual (REPA).\u0000The results show that ERA5 presents a better correlation for annual mean temperature (between 0.74-0.90) compared to WFDE5 (0.63-0.78) and MERRA2 (0.25-0.65). Both ERA5 and WFDE5 are able to reproduce the observed upward trend of temperature (0.2°C/decade) in the region. We noted a systematic cold bias of ~1.3°C in all reanalyses except WFDE5 (~0.1°C). On the monthly timescale, the temperature of the region is better reproduced by ERA5 and WFDE5 (KGE ≥ 0.80) compared to MERRA2 (KGE < 0.5). At all timescales, WFDE5 produces the best MAE scores for longwave (LW) and shortwave (SW) radiation followed by ERA5. WFDE5 also provides the best estimates for the annual precipitation (REPA ∈ ]-25, 25[ and KGE ≥ 50% at most stations). ERA5 produces similar results, but MERRA2 performs poorly in all the metrics. Additionally, ERA5 and WFDE5 reproduce the bimodal rainfall regime in southern Benin, unlike MERRA2, but all products have too many small rainfall events.","PeriodicalId":15027,"journal":{"name":"Journal of Applied Meteorology and Climatology","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43579422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-27DOI: 10.1175/jamc-d-23-0067.1
M. Kiefer, J. Andresen, D. McCullough, James B. Wieferich, Justin Keyzer, S. Marquie
Gridded climate datasets are used by researchers and practitioners in many disciplines, including forest ecology, agriculture, and entomology. However, such datasets are generally unable to account for microclimatic variability, particularly within sites or among individual trees. One such dataset is a recent climatology of extreme minimum temperatures in the United States Great Lakes region, based on the Parameter-elevation Regressions on Independent Slopes Model (PRISM) gridded temperature dataset. Development of this climatology was motivated by interest in the spatiotemporal variability of winter temperatures potentially lethal to the hemlock woolly adelgid (HWA) (Adelges tsugae Annand) (Hemiptera: Adelgidae), an invasive insect that causes mortality of eastern hemlock (Tsuga canadensis). In this study, cold-season daily minimum temperatures were monitored at six Michigan sites varying in latitude, elevation, Great Lakes proximity, and HWA infestation status, to address two objectives. First, we documented the spatiotemporal variability in daily minimum air temperatures recorded at multiple aspects and heights on selected hemlock trees. Second, this variability was characterized in the context of the PRISM extreme minimum temperature climatology. Tree-sensor air temperatures exhibited minimal relationships with aspect, but considerable sensitivity to height. Daily minimum temperatures were higher for some tree sensors positioned ≤ 0.2 m above ground level during some time periods, with overall muted temporal variability, compared to an adjacent ambient sensor. This phenomenon was attributed to insulating effects of snow cover, as tree-ambient sensor temperature difference was positively correlated with snow depth. Overall, results indicate that such unresolved variability warrants consideration by gridded climate dataset users.
{"title":"Microclimatic Variability of Cold-Season Minimum Temperatures in Michigan, United States: A Study with Implications for Insect Mortality","authors":"M. Kiefer, J. Andresen, D. McCullough, James B. Wieferich, Justin Keyzer, S. Marquie","doi":"10.1175/jamc-d-23-0067.1","DOIUrl":"https://doi.org/10.1175/jamc-d-23-0067.1","url":null,"abstract":"\u0000Gridded climate datasets are used by researchers and practitioners in many disciplines, including forest ecology, agriculture, and entomology. However, such datasets are generally unable to account for microclimatic variability, particularly within sites or among individual trees. One such dataset is a recent climatology of extreme minimum temperatures in the United States Great Lakes region, based on the Parameter-elevation Regressions on Independent Slopes Model (PRISM) gridded temperature dataset. Development of this climatology was motivated by interest in the spatiotemporal variability of winter temperatures potentially lethal to the hemlock woolly adelgid (HWA) (Adelges tsugae Annand) (Hemiptera: Adelgidae), an invasive insect that causes mortality of eastern hemlock (Tsuga canadensis). In this study, cold-season daily minimum temperatures were monitored at six Michigan sites varying in latitude, elevation, Great Lakes proximity, and HWA infestation status, to address two objectives. First, we documented the spatiotemporal variability in daily minimum air temperatures recorded at multiple aspects and heights on selected hemlock trees. Second, this variability was characterized in the context of the PRISM extreme minimum temperature climatology. Tree-sensor air temperatures exhibited minimal relationships with aspect, but considerable sensitivity to height. Daily minimum temperatures were higher for some tree sensors positioned ≤ 0.2 m above ground level during some time periods, with overall muted temporal variability, compared to an adjacent ambient sensor. This phenomenon was attributed to insulating effects of snow cover, as tree-ambient sensor temperature difference was positively correlated with snow depth. Overall, results indicate that such unresolved variability warrants consideration by gridded climate dataset users.","PeriodicalId":15027,"journal":{"name":"Journal of Applied Meteorology and Climatology","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2023-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47534554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-27DOI: 10.1175/jamc-d-22-0190.1
Lea Hartl, Carl Schmitt, Telayna Wong, D. Vas, Lewis Enterkin, M. Stuefer
Ice fog typically occurs at temperatures below about −30°C. Ice fog formation and persistence are affected by atmospheric processes at different spatial and temporal scales and can be influenced by anthropogenic activities that add vapor to the near surface atmosphere. Based on meteorological observations from Fairbanks International Airport and Eielson Air Force Base (Alaska, USA) from 1948/49 to 2021/22, we provide an overview of general ice fog climatology at the sites, changes over time, and synoptic scale upper-level weather patterns common during ice fog occurrence. On average, ice fog occurrence has decreased by 60-70% over the study period (median number of ice fog days at Fairbanks Airport in 1950/51-1979/80: 16.5; median in 1990/91-2019/20: 6). The average length of ice fog events and of the ice fog season have also decreased. Trends are not linear and rates of change vary over time. The greatest reduction in ice fog occurred during the 1970s and ‘80s. Trends in ice fog hours roughly track decreasing trends in hours with cold temperatures. However, the percentage of cold hours in which ice fog occurs has decreased since about the 1980s. This suggests that local changes in air pollution or near-surface moisture may also play an important role for trends in ice fog occurrence. We use self organizing maps to assess recurring synoptic scale weather patterns in the upper atmosphere during ice fog conditions in Fairbanks. Ice fog is typically associated with a northerly flow or low pressure gradients over the study area.
{"title":"Long term trends in ice fog occurrence in the Fairbanks, Alaska, region based on airport observations","authors":"Lea Hartl, Carl Schmitt, Telayna Wong, D. Vas, Lewis Enterkin, M. Stuefer","doi":"10.1175/jamc-d-22-0190.1","DOIUrl":"https://doi.org/10.1175/jamc-d-22-0190.1","url":null,"abstract":"\u0000Ice fog typically occurs at temperatures below about −30°C. Ice fog formation and persistence are affected by atmospheric processes at different spatial and temporal scales and can be influenced by anthropogenic activities that add vapor to the near surface atmosphere. Based on meteorological observations from Fairbanks International Airport and Eielson Air Force Base (Alaska, USA) from 1948/49 to 2021/22, we provide an overview of general ice fog climatology at the sites, changes over time, and synoptic scale upper-level weather patterns common during ice fog occurrence. On average, ice fog occurrence has decreased by 60-70% over the study period (median number of ice fog days at Fairbanks Airport in 1950/51-1979/80: 16.5; median in 1990/91-2019/20: 6). The average length of ice fog events and of the ice fog season have also decreased. Trends are not linear and rates of change vary over time. The greatest reduction in ice fog occurred during the 1970s and ‘80s. Trends in ice fog hours roughly track decreasing trends in hours with cold temperatures. However, the percentage of cold hours in which ice fog occurs has decreased since about the 1980s. This suggests that local changes in air pollution or near-surface moisture may also play an important role for trends in ice fog occurrence. We use self organizing maps to assess recurring synoptic scale weather patterns in the upper atmosphere during ice fog conditions in Fairbanks. Ice fog is typically associated with a northerly flow or low pressure gradients over the study area.","PeriodicalId":15027,"journal":{"name":"Journal of Applied Meteorology and Climatology","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2023-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44314082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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