The existence of three well-defined tongue-shaped zones of swell dominance,termed as 'swell pools',in the Pacific,the Atlantic and the Indian Oceans,was reported by Chen et al.(2002)using satellite data.In thi...The existence of three well-defined tongue-shaped zones of swell dominance,termed as 'swell pools',in the Pacific,the Atlantic and the Indian Oceans,was reported by Chen et al.(2002)using satellite data.In this paper,the ECMWF Re-analyses wind wave data,including wind speed,significant wave height,averaged wave period and direction,are applied to verify the existence of these swell pools.The swell indices calculated from wave height,wave age and correlation coefficient are used to identify swell events.The wave age swell index can be more appropriately related to physical processes compared to the other two swell indices.Based on the ECMWF data the swell pools in the Pacific and the Atlantic Oceans are confirmed,but the expected swell pool in the Indian Ocean is not pronounced.The seasonal variations of global and hemispherical swell indices are investigated,and the argument that swells in the pools seemed to originate mostly from the winter hemisphere is supported by the seasonal variation of the averaged wave direction.The northward bending of the swell pools in the Pacific and the Atlantic Oceans in summer is not revealed by the ECMWF data.The swell pool in the Indian Ocean and the summer northward bending of the swell pools in the Pacific and the Atlan-tic Oceans need to be further verified by other datasets.展开更多
[目的/意义]在全球气候变暖的大背景下,准确确定冬小麦的适宜播种期对于提高小麦产量、保障国家粮食安全具有重要意义。本研究旨在对县级镇在气候变暖长时间序列影响下冬小麦适宜播种期进行分析。[方法]本研究以山东省齐河县为研究区域...[目的/意义]在全球气候变暖的大背景下,准确确定冬小麦的适宜播种期对于提高小麦产量、保障国家粮食安全具有重要意义。本研究旨在对县级镇在气候变暖长时间序列影响下冬小麦适宜播种期进行分析。[方法]本研究以山东省齐河县为研究区域,基于1997—2022年的欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)再分析数据,首先,采用温度阈值法确定稳定通过18、16、14和0℃终日的日期,并从不同小麦品种的适宜播种温度、不同日期播种至越冬前≥0℃的积温、适播期历年日平均气温等关键播期指标对冬小麦适宜播种期进行统计分析;其次,利用叶龄积温法对冬前壮苗所需合适积温的日期进行测算;最后,结合实际生产实践情况,确定气候变暖趋势下齐河县各乡镇冬小麦的适宜播种期。[结果和讨论]从小麦适宜播种温度、播种至小麦越冬停止生长0℃的积温等农业气象指标,以及考虑齐河县种植的冬小麦品种,得出齐河县冬小麦适宜播种期为10月3日—10月16日,最佳播种期为10月5日—10月13日。但具体年份的适播期还需要依据当年的具体情况灵活播种。[结论]研究结果证明了温度阈值法和叶龄积温法在确定冬小麦适宜播种期研究中的可行性,通过温度变化趋势可判断冷冬或暖冬,及时调整播种时间以提高小麦产量,减少温度过高或过低对冬小麦的影响。本研究不仅可以为齐河县冬小麦产量评估提供决策参考,还可以为科学安排农业生产提供重要的理论依据。展开更多
New satellite-derived latent and sensible heat fluxes are performed by using Wind Sat wind speed, Wind Sat sea surface temperature, the European Centre for Medium-range Weather Forecasting（ECMWF） air humidity, and E...New satellite-derived latent and sensible heat fluxes are performed by using Wind Sat wind speed, Wind Sat sea surface temperature, the European Centre for Medium-range Weather Forecasting（ECMWF） air humidity, and ECMWF air temperature from 2004 to 2014. The 55 moored buoys are used to validate them by using the 30 min and 25 km collocation window. Furthermore, the objectively analyzed air-sea heat fluxes（OAFlux） products and the National Centers for Environmental Prediction-National Center for Atmospheric Research reanalysis 2（NCEP2） products are also used for global comparisons. The mean biases of sensible and latent heat fluxes between Wind Sat flux results and buoy flux data are –0.39 and –8.09 W/m^2, respectively. In addition, the rootmean-square（RMS） errors of the sensible and latent heat fluxes between them are 5.53 and 24.69 W/m^2,respectively. The RMS errors of sensible and latent heat fluxes are observed to gradually increase with an increasing buoy wind speed. The difference shows different characteristics with an increasing sea surface temperature, air humidity, and air temperature. The zonal average latent fluxes have some high regions which are mainly located in the trade wind zones where strong winds carry dry air in January, and the maximum value centers are found in the eastern waters of Japan and on the US east coast. Overall, the seasonal variability is pronounced in the Indian Ocean, the Pacific Ocean, and the Atlantic Ocean. The three sensible and latent heat fluxes have similar latitudinal dependencies; however, some differences are found in some local regions.展开更多
新疆地区生态环境脆弱且对气候变化敏感,在全球气候变化背景下,新疆生态环境及水资源可持续发展方面均面临巨大的挑战。以新疆降水为重点研究对象,应用欧洲中期数值预报中心(European Centre for Medium-range Weather Forecasts,ECMWF...新疆地区生态环境脆弱且对气候变化敏感,在全球气候变化背景下,新疆生态环境及水资源可持续发展方面均面临巨大的挑战。以新疆降水为重点研究对象,应用欧洲中期数值预报中心(European Centre for Medium-range Weather Forecasts,ECMWF)的全球再分析气象数据(ECMWF Re-Analysis-Interim)探究新疆的降水变化规律。研究结果表明:新疆地区南北疆、山地、平原、盆地、荒漠和沙漠不同地域的气候差异极为显著,北疆的降水量多于南疆,西部的降水量多于东部。其中,西部伊犁地区降水量达东部哈密地区的近6倍;此外,山区降水量远多于盆地,天山山区的年降水量约235.65 mm。通过分析1979—2013年降水量数据时间序列和月、季度、年各气候区划的降水量均值和变化趋势发现,新疆不同气候区划的降水量差异显著。其中,天山北坡气候区降水充沛,多年平均降水量达278.52 mm,为新疆降水量最多的气候区,阿尔泰山气候区次之,多年平均降水量达221.91 mm,北疆准噶尔盆地气候区的年降水量为181.87 mm,而南疆塔里木盆地气候区的多年平均降水量仅为66.03 mm。本研究总体认为:新疆降水量时空分布呈现北疆多、南疆少,山地多、平原少,夏季多、冬季少的时空分布特征。研究结果将为新疆水资源对气候变化的响应研究起到重要的推动作用。展开更多
基金the National Natural Science Foundation of China (Nos. 40830959 and 40921004)the Ministry of Science and Technology of China (No. 2011BAC03B01)
文摘The existence of three well-defined tongue-shaped zones of swell dominance,termed as 'swell pools',in the Pacific,the Atlantic and the Indian Oceans,was reported by Chen et al.(2002)using satellite data.In this paper,the ECMWF Re-analyses wind wave data,including wind speed,significant wave height,averaged wave period and direction,are applied to verify the existence of these swell pools.The swell indices calculated from wave height,wave age and correlation coefficient are used to identify swell events.The wave age swell index can be more appropriately related to physical processes compared to the other two swell indices.Based on the ECMWF data the swell pools in the Pacific and the Atlantic Oceans are confirmed,but the expected swell pool in the Indian Ocean is not pronounced.The seasonal variations of global and hemispherical swell indices are investigated,and the argument that swells in the pools seemed to originate mostly from the winter hemisphere is supported by the seasonal variation of the averaged wave direction.The northward bending of the swell pools in the Pacific and the Atlantic Oceans in summer is not revealed by the ECMWF data.The swell pool in the Indian Ocean and the summer northward bending of the swell pools in the Pacific and the Atlan-tic Oceans need to be further verified by other datasets.
文摘[目的/意义]在全球气候变暖的大背景下,准确确定冬小麦的适宜播种期对于提高小麦产量、保障国家粮食安全具有重要意义。本研究旨在对县级镇在气候变暖长时间序列影响下冬小麦适宜播种期进行分析。[方法]本研究以山东省齐河县为研究区域,基于1997—2022年的欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)再分析数据,首先,采用温度阈值法确定稳定通过18、16、14和0℃终日的日期,并从不同小麦品种的适宜播种温度、不同日期播种至越冬前≥0℃的积温、适播期历年日平均气温等关键播期指标对冬小麦适宜播种期进行统计分析;其次,利用叶龄积温法对冬前壮苗所需合适积温的日期进行测算;最后,结合实际生产实践情况,确定气候变暖趋势下齐河县各乡镇冬小麦的适宜播种期。[结果和讨论]从小麦适宜播种温度、播种至小麦越冬停止生长0℃的积温等农业气象指标,以及考虑齐河县种植的冬小麦品种,得出齐河县冬小麦适宜播种期为10月3日—10月16日,最佳播种期为10月5日—10月13日。但具体年份的适播期还需要依据当年的具体情况灵活播种。[结论]研究结果证明了温度阈值法和叶龄积温法在确定冬小麦适宜播种期研究中的可行性,通过温度变化趋势可判断冷冬或暖冬,及时调整播种时间以提高小麦产量,减少温度过高或过低对冬小麦的影响。本研究不仅可以为齐河县冬小麦产量评估提供决策参考,还可以为科学安排农业生产提供重要的理论依据。
基金The National Natural Science Foundation of China under contract No.41576171
文摘New satellite-derived latent and sensible heat fluxes are performed by using Wind Sat wind speed, Wind Sat sea surface temperature, the European Centre for Medium-range Weather Forecasting（ECMWF） air humidity, and ECMWF air temperature from 2004 to 2014. The 55 moored buoys are used to validate them by using the 30 min and 25 km collocation window. Furthermore, the objectively analyzed air-sea heat fluxes（OAFlux） products and the National Centers for Environmental Prediction-National Center for Atmospheric Research reanalysis 2（NCEP2） products are also used for global comparisons. The mean biases of sensible and latent heat fluxes between Wind Sat flux results and buoy flux data are –0.39 and –8.09 W/m^2, respectively. In addition, the rootmean-square（RMS） errors of the sensible and latent heat fluxes between them are 5.53 and 24.69 W/m^2,respectively. The RMS errors of sensible and latent heat fluxes are observed to gradually increase with an increasing buoy wind speed. The difference shows different characteristics with an increasing sea surface temperature, air humidity, and air temperature. The zonal average latent fluxes have some high regions which are mainly located in the trade wind zones where strong winds carry dry air in January, and the maximum value centers are found in the eastern waters of Japan and on the US east coast. Overall, the seasonal variability is pronounced in the Indian Ocean, the Pacific Ocean, and the Atlantic Ocean. The three sensible and latent heat fluxes have similar latitudinal dependencies; however, some differences are found in some local regions.
文摘河南连续运行参考系统(Continuously Operating Reference Stations,CORS)有63个测站,但仅有6个测站安装有气象传感器,而且数据极其不完整,而气象数据对于(Global Positioning System,GPS)反演水汽十分重要。针对这一问题,研究了利用欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)的再分析资料插值河南测站的气象参数和大气可降水量(Precipitable Water Vapor,PWV)。研究结果表明:插值的气压平均偏差和均方根误差在1 hpa以内,气温平均偏差和均方根误差在5 K左右;针对气温插值结果偏差稍大的问题,对插值温度进行改正,能提高50%左右的精度;将实测气象参数的GPS/PWV和无线电探空的Radio/PWV作为真值,证明了利用插值的气象参数估计河南地区GPS/PWV的精度完全满足需求,进一步提高河南CORS系统在气象方面的应用价值。
