Considering the characteristics of nonlinear problems,a new method based on the L-curve method and including the concept of entropy was designed to select the regularization parameter in the one-dimensional variationa...Considering the characteristics of nonlinear problems,a new method based on the L-curve method and including the concept of entropy was designed to select the regularization parameter in the one-dimensional variational analysis-based sounding retrieval method.In the first iteration,this method uses an empirical regularization parameter derived by minimizing the entropy of variables.During subsequent iterations,it uses the L-curve method to select the regularization parameter in the vicinity of the regularization parameter selected in the last iteration.The new method was employed to select the regularization parameter in retrieving atmospheric temperature and moisture profiles from Atmospheric Infrared Sounder radiance measurements selected from the first day of each month in 2008.The results show that compared with the original L-curve method,the new method yields 5.5%and 2.5%improvements on temperature and relative humidity profiles,respectively.Compared with the discrepancy principle method,the improvements on temperature and relative humidity profiles are 1.6%and 2.0%,respectively.展开更多
The atmospheric infrared sounder （AIRS） instrument onboard Aqua Satellite is a high spectral resolution infrared sounder. In recent years, AIRS has gradually become the primary method of atmospheric vertical observa...The atmospheric infrared sounder （AIRS） instrument onboard Aqua Satellite is a high spectral resolution infrared sounder. In recent years, AIRS has gradually become the primary method of atmospheric vertical observations. To examine the validation of AIRS retrieval products （V3.0） over China, the AIRS surface air temperature retrievals were compared with the ground observations obtained from 540 meteorological stations in July 2004 and January 2005, respectively. The sources of errors were considerably discussed. Based on the error analysis, the AIRS retrieved surface air temperature products were systemically corrected. Moreover, the AIRS temperature and humidity profile retrievals were compared with T213 numerical forecasting products. Because T213 forecasting products are not the actual atmospheric states, to further verify the validation, the AIRS temperature and humidity profile products were assimilated into the MM5 model through the analysis nudging. In this paper, the case on February 14, 2005 in North China was simulated in detail. Then, we investigated the effects of AIRS retrievals on snowfall, humidity field, vertical velocity field, divergence field, and cloud microphysical processes. The major results are： （1） the errors of AIRS retrieved surface air temperature products are largely systematic deviations, for which the influences of terrain altitude and surface types are the major reasons; （2） the differences between the AIRS atmospheric profile retrievals and T213 numerical prediction products in temperature are generally less than 2 K, the differences in relative humidity are generally less than 25%; and （3） the AIRS temperature and humidity retrieval products can adjust the model initial field, and thus can improve the capacity of snowfall simulation to some extent.展开更多
This research utilizes geospatial methodologies to investigate the influence of gas flaring and carbon dioxide emissions on precipitation patterns within the Niger Delta region of Nigeria.The study relies on average m...This research utilizes geospatial methodologies to investigate the influence of gas flaring and carbon dioxide emissions on precipitation patterns within the Niger Delta region of Nigeria.The study relies on average mean precipitation data sourced from CHRS at the University of Arizona and carbon dioxide emissions data from NASA’s AIRS in Giovanni,spanning from July 2002 to November 2011.To carry out the analysis,ArcGIS 5.0 and SPSS 25,employing Inverse Distance Weighting(IDW),were employed to assess CO_(2) emissions and rainfall for both November and July during the period from 2002 to 2011.Over the course of this study,it was observed that CO_(2) emission exhibited an upward trend,increasing from 327.5226 parts per million(ppm)in July 2002 to 390.0077 ppm in November 2011.Simultaneously,the rainfall demonstrated an increase,rising from 56.66 millimeters to 390.78 millimeters for both July and November from 2002 to 2011.Noteworthy findings emerged from the correlation analysis conducted.Specifically,from July 2000 to 2011,there was a weak positive correlation(0.3858)observed between CO_(2) emissions and minimum rainfall,while a strong negative correlation(–0.7998)was identified for maximum rainfall values.In November,both minimum and maximum CO_(2) emissions displayed strong negative correlations with rainfall,with coefficients of–0.8255 and–0.7415,respectively.These findings hold significant implications for comprehending the environmental dynamics within the Niger Delta.Policymakers and stakeholders can leverage this knowledge to formulate targeted strategies aimed at mitigating CO_(2) emissions and addressing potential climate change-induced alterations in rainfall patterns.展开更多
GRAPES(Globe and Regional Assimilation and Prediction System)变分系统能够同化常规资料和非常规卫星资料,这些被同化的资料究竟对同化系统得到的分析场有何影响,目前国内外尚未见相关的研究文献。为此,首次采用基于信息熵信号自由...GRAPES(Globe and Regional Assimilation and Prediction System)变分系统能够同化常规资料和非常规卫星资料,这些被同化的资料究竟对同化系统得到的分析场有何影响,目前国内外尚未见相关的研究文献。为此,首次采用基于信息熵信号自由度思想,诊断风云三号B星(FY3B)红外分光计(Infrared Atmospheric Sounder,IRAS)资料对GRAPES分析场的影响。诊断过程中,采用数值逼近方法,统计2012年12月24日18时到2013年1月22日00时共114个时次IRAS资料对GRAPES分析场影响,结果表明,IRAS中高层通道亮温资料对GRAPES分析场影响比地表通道20观测亮温的影响大,地表通道8和9观测亮温对分析场影响较大。前24个GRAPES变分同化时次每个时次IRAS通道亮温对分析场影响的贡献率分析结果显示,高层通道和H_2O通道贡献率较大。个例分析结果表明,在同化探空资料基础上加入IRAS资料后,温度和湿度增量场变化幅度较大,表明IRAS资料对分析场有降温和增湿作用。展开更多
基金Supported by the China Meteorological Administration Special Public Welfare Research Fund(GYHY201406011)National Natural Science Foundation of China(41405038)
文摘Considering the characteristics of nonlinear problems,a new method based on the L-curve method and including the concept of entropy was designed to select the regularization parameter in the one-dimensional variational analysis-based sounding retrieval method.In the first iteration,this method uses an empirical regularization parameter derived by minimizing the entropy of variables.During subsequent iterations,it uses the L-curve method to select the regularization parameter in the vicinity of the regularization parameter selected in the last iteration.The new method was employed to select the regularization parameter in retrieving atmospheric temperature and moisture profiles from Atmospheric Infrared Sounder radiance measurements selected from the first day of each month in 2008.The results show that compared with the original L-curve method,the new method yields 5.5%and 2.5%improvements on temperature and relative humidity profiles,respectively.Compared with the discrepancy principle method,the improvements on temperature and relative humidity profiles are 1.6%and 2.0%,respectively.
基金the National Natural Science Foundation of China under Grant No. 40271079.
文摘The atmospheric infrared sounder （AIRS） instrument onboard Aqua Satellite is a high spectral resolution infrared sounder. In recent years, AIRS has gradually become the primary method of atmospheric vertical observations. To examine the validation of AIRS retrieval products （V3.0） over China, the AIRS surface air temperature retrievals were compared with the ground observations obtained from 540 meteorological stations in July 2004 and January 2005, respectively. The sources of errors were considerably discussed. Based on the error analysis, the AIRS retrieved surface air temperature products were systemically corrected. Moreover, the AIRS temperature and humidity profile retrievals were compared with T213 numerical forecasting products. Because T213 forecasting products are not the actual atmospheric states, to further verify the validation, the AIRS temperature and humidity profile products were assimilated into the MM5 model through the analysis nudging. In this paper, the case on February 14, 2005 in North China was simulated in detail. Then, we investigated the effects of AIRS retrievals on snowfall, humidity field, vertical velocity field, divergence field, and cloud microphysical processes. The major results are： （1） the errors of AIRS retrieved surface air temperature products are largely systematic deviations, for which the influences of terrain altitude and surface types are the major reasons; （2） the differences between the AIRS atmospheric profile retrievals and T213 numerical prediction products in temperature are generally less than 2 K, the differences in relative humidity are generally less than 25%; and （3） the AIRS temperature and humidity retrieval products can adjust the model initial field, and thus can improve the capacity of snowfall simulation to some extent.
文摘This research utilizes geospatial methodologies to investigate the influence of gas flaring and carbon dioxide emissions on precipitation patterns within the Niger Delta region of Nigeria.The study relies on average mean precipitation data sourced from CHRS at the University of Arizona and carbon dioxide emissions data from NASA’s AIRS in Giovanni,spanning from July 2002 to November 2011.To carry out the analysis,ArcGIS 5.0 and SPSS 25,employing Inverse Distance Weighting(IDW),were employed to assess CO_(2) emissions and rainfall for both November and July during the period from 2002 to 2011.Over the course of this study,it was observed that CO_(2) emission exhibited an upward trend,increasing from 327.5226 parts per million(ppm)in July 2002 to 390.0077 ppm in November 2011.Simultaneously,the rainfall demonstrated an increase,rising from 56.66 millimeters to 390.78 millimeters for both July and November from 2002 to 2011.Noteworthy findings emerged from the correlation analysis conducted.Specifically,from July 2000 to 2011,there was a weak positive correlation(0.3858)observed between CO_(2) emissions and minimum rainfall,while a strong negative correlation(–0.7998)was identified for maximum rainfall values.In November,both minimum and maximum CO_(2) emissions displayed strong negative correlations with rainfall,with coefficients of–0.8255 and–0.7415,respectively.These findings hold significant implications for comprehending the environmental dynamics within the Niger Delta.Policymakers and stakeholders can leverage this knowledge to formulate targeted strategies aimed at mitigating CO_(2) emissions and addressing potential climate change-induced alterations in rainfall patterns.
文摘GRAPES(Globe and Regional Assimilation and Prediction System)变分系统能够同化常规资料和非常规卫星资料,这些被同化的资料究竟对同化系统得到的分析场有何影响,目前国内外尚未见相关的研究文献。为此,首次采用基于信息熵信号自由度思想,诊断风云三号B星(FY3B)红外分光计(Infrared Atmospheric Sounder,IRAS)资料对GRAPES分析场的影响。诊断过程中,采用数值逼近方法,统计2012年12月24日18时到2013年1月22日00时共114个时次IRAS资料对GRAPES分析场影响,结果表明,IRAS中高层通道亮温资料对GRAPES分析场影响比地表通道20观测亮温的影响大,地表通道8和9观测亮温对分析场影响较大。前24个GRAPES变分同化时次每个时次IRAS通道亮温对分析场影响的贡献率分析结果显示,高层通道和H_2O通道贡献率较大。个例分析结果表明,在同化探空资料基础上加入IRAS资料后,温度和湿度增量场变化幅度较大,表明IRAS资料对分析场有降温和增湿作用。
