The cultivated area is an important component of land resources that has a direct impact on food security. Egyptian cultivated area was estimated to be 3.86 million hectares in 2020. Recently, there has been a decline...The cultivated area is an important component of land resources that has a direct impact on food security. Egyptian cultivated area was estimated to be 3.86 million hectares in 2020. Recently, there has been a decline in cultivated areas, which could be attributed to a number of factors, including climatic changes and urban sprawl, endangering Egyptian sustainable development. So, the aim of the current study was to forecast the values of cultivated areas in Egypt for the next five years using the ARIMA model based on data from 1990 to 2020. The model predicted a decrease in cultivated area in coming years of about 3.06, 3.19, 3.084, 3.082 and 3.21 million hectares, respectively, according to the results. This forecasting will aid the country’s policy development for future land using planning and agricultural production.展开更多
The purpose of this paper is to study the air pollutants in Xiong’an New Area based on MATLAB grey model [1]. From 2011 to 2016, the results of sulfur dioxide (SO2), nitrogen dioxide (NO2) and inhalable particulate m...The purpose of this paper is to study the air pollutants in Xiong’an New Area based on MATLAB grey model [1]. From 2011 to 2016, the results of sulfur dioxide (SO2), nitrogen dioxide (NO2) and inhalable particulate matter (PM1O) detected at monitoring points in the three counties of Xiong’an were analyzed. According to the national environmental air quality standard [2], the air quality in Xiong’an New Area was reasonably evaluated based on grey model in MATLAB. Judging from the weight of pollution factors in the model, sulfur dioxide (SO2) is the controlling factor of air quality in Xiong’an New Area, and the weight of nitrogen dioxide (NO2) gradually increases. The main sources of the three pollutants were obtained by comprehensive data analysis, and a grey model was established according to the mass concentration of the main air pollutants, and the grey forecasting model was tested. The experimental results show that the model can be effectively applied to the forecasting of ambient air quality. On this basis, the present situation of atmospheric environmental quality in Xiong’an New Area and suggestions for improvement are obtained.展开更多
基于欧洲中期天气预报中心(ECMWF)、中国气象局(CMA)、日本气象厅(JMA)、美国国家环境预报中心(NCEP)、英国气象局(UKMO)五个模式集成的交互式全球大集合预报系统(THORPEX Interactive Grand Global Ensemble,简称TIGGE)资料集的确定性...基于欧洲中期天气预报中心(ECMWF)、中国气象局(CMA)、日本气象厅(JMA)、美国国家环境预报中心(NCEP)、英国气象局(UKMO)五个模式集成的交互式全球大集合预报系统(THORPEX Interactive Grand Global Ensemble,简称TIGGE)资料集的确定性预报、集合预报以及地面降水观测数据,采用多模式集成平均(EMN)、消除偏差集成平均(BREM)、滑动训练期超级集合方法(R_SUP)对2018年华南汛期(4—9月)粤港澳大湾区的降水预报开展了评估检验。总体而言,多模式集成预报方法在大湾区前汛期降水预报的均方根误差平均比后汛期高2 mm;多模式集成预报方法的预报能力在前汛期随着预报时效的延长而呈持续下降趋势,后汛期则表现为短期(24~72 h)下降、中期(72~168 h)持续平稳的变化特点。与预先的假设差异主要表现在:对前、后汛期的降水预报综合表现最好的均是数学原理相对简单的EMN,而BREM和R_SUP的空间平均评分指标则稍差,但其在降水落区预报中仍有较好的预报技巧。展开更多
With a mesoscale model (MM5) nested with the global spectral model of NationalMeteorological Center/CMA and especially with the forecast experiments as to rainfall andtemperature of twenty-seven sampling stations in E...With a mesoscale model (MM5) nested with the global spectral model of NationalMeteorological Center/CMA and especially with the forecast experiments as to rainfall andtemperature of twenty-seven sampling stations in East China for six months (February, March,April in 1997 and June, July, August in 1998), it has been found that the better prediction can beperformed on the condition that the surface physical process of practical land-use categories andphysical parameters is parameterized in particular forecast domain. limited-area model, land-use category, forecast展开更多
文摘The cultivated area is an important component of land resources that has a direct impact on food security. Egyptian cultivated area was estimated to be 3.86 million hectares in 2020. Recently, there has been a decline in cultivated areas, which could be attributed to a number of factors, including climatic changes and urban sprawl, endangering Egyptian sustainable development. So, the aim of the current study was to forecast the values of cultivated areas in Egypt for the next five years using the ARIMA model based on data from 1990 to 2020. The model predicted a decrease in cultivated area in coming years of about 3.06, 3.19, 3.084, 3.082 and 3.21 million hectares, respectively, according to the results. This forecasting will aid the country’s policy development for future land using planning and agricultural production.
文摘The purpose of this paper is to study the air pollutants in Xiong’an New Area based on MATLAB grey model [1]. From 2011 to 2016, the results of sulfur dioxide (SO2), nitrogen dioxide (NO2) and inhalable particulate matter (PM1O) detected at monitoring points in the three counties of Xiong’an were analyzed. According to the national environmental air quality standard [2], the air quality in Xiong’an New Area was reasonably evaluated based on grey model in MATLAB. Judging from the weight of pollution factors in the model, sulfur dioxide (SO2) is the controlling factor of air quality in Xiong’an New Area, and the weight of nitrogen dioxide (NO2) gradually increases. The main sources of the three pollutants were obtained by comprehensive data analysis, and a grey model was established according to the mass concentration of the main air pollutants, and the grey forecasting model was tested. The experimental results show that the model can be effectively applied to the forecasting of ambient air quality. On this basis, the present situation of atmospheric environmental quality in Xiong’an New Area and suggestions for improvement are obtained.
文摘基于欧洲中期天气预报中心(ECMWF)、中国气象局(CMA)、日本气象厅(JMA)、美国国家环境预报中心(NCEP)、英国气象局(UKMO)五个模式集成的交互式全球大集合预报系统(THORPEX Interactive Grand Global Ensemble,简称TIGGE)资料集的确定性预报、集合预报以及地面降水观测数据,采用多模式集成平均(EMN)、消除偏差集成平均(BREM)、滑动训练期超级集合方法(R_SUP)对2018年华南汛期(4—9月)粤港澳大湾区的降水预报开展了评估检验。总体而言,多模式集成预报方法在大湾区前汛期降水预报的均方根误差平均比后汛期高2 mm;多模式集成预报方法的预报能力在前汛期随着预报时效的延长而呈持续下降趋势,后汛期则表现为短期(24~72 h)下降、中期(72~168 h)持续平稳的变化特点。与预先的假设差异主要表现在:对前、后汛期的降水预报综合表现最好的均是数学原理相对简单的EMN,而BREM和R_SUP的空间平均评分指标则稍差,但其在降水落区预报中仍有较好的预报技巧。
文摘With a mesoscale model (MM5) nested with the global spectral model of NationalMeteorological Center/CMA and especially with the forecast experiments as to rainfall andtemperature of twenty-seven sampling stations in East China for six months (February, March,April in 1997 and June, July, August in 1998), it has been found that the better prediction can beperformed on the condition that the surface physical process of practical land-use categories andphysical parameters is parameterized in particular forecast domain. limited-area model, land-use category, forecast
