中国大陆及邻GRACE卫星重力变化研究

探讨如何运用GRACE数据进行重力变化的计算和分析.对GRACE重力场位系数的最大阶次选取进行了分析,并利用月卫星重力场模型计算了中国大陆及邻区的重力变化,通过平均半径为800km的高斯平滑,得出了合理的重力变化结果.     

Assimilation of NCEP multi-sensor hourly rainfall data using 4D-Var approach: A case study of the squall line on April 5, 1999

Summary ?NCEP multi-sensor hourly rainfall data were used for data assimilation and evaluation of quantitative precipitation forecasts (QPFs) through a case study of a squall line on April 5, 1999. Improvements in QPFs were obtained through direct assimilation of these rainfall observations using 4-dimensional variational assimilation (4D-Var). Inclusion of the observed no-rain information was shown to be beneficial to QPFs. While the penalty constraint applying a digital filter was effective in removing high frequency oscillations introduced by rainfall assimilation and produced a smoother “optimal” initial condition, its impact on QPFs is mixed. Sensitivity studies indicated that the adjustments in the moisture and temperature fields resulted from precipitation assimilation played a more important role than those of other state variables for improving QPFs. Received October 27, 2001; accepted January 30, 2002     

运用气象信息确定最优农业种植决策

根据益阳县农科所耕地面积、种植方式等资料，在运用线性规划原理优化农业种植决策的基础上，考虑气候资料和天气预报信息，运用运筹学单点图形法确定最优农业种植决策，可获得明显的经济效益。     

Development and initial assessment of a new land index for microwave humidity sounder cloud detection

This paper describes a new quality control (QC) scheme for microwave humidity sounder (MHS) data assimilation. It consists of a cloud detection step and an O–B (i.e., differences of brightness temperatures between observations and model simulations) check. Over ocean, cloud detection can be carried out based on two MHS window channels and two Advanced Microwave Sounding Unit-A (AMSU-A) window channels, which can be used for obtaining cloud ice water path (IWP) and liquid water path (LWP), respectively. Over land, cloud detection of microwave data becomes much more challenging due to a much larger emission contribution from land surface than that from cloud. The current MHS cloud detection over land employs an O–B based method, which could fail to identify cloudy radiances when there is mismatch between actual clouds and model clouds. In this study, a new MHS observation based index is developed for identifying MHS cloudy radiances over land. The new land index for cloud detection exploits the large variability of brightness temperature observations among MHS channels over different clouds. It is shown that those MHS cloudy radiances that were otherwise missed by the current O–B based QC method can be successfully identified by the new land index. An O–B check can then be employed to the remaining data after cloud detection to remove additional outliers with model simulations deviated greatly from observations. It is shown that MHS channel correlations are significantly reduced by the newly proposed QC scheme.     

中国山地环境气象研究进展

中国山地环境气象学是研究中国山地与大气、自然环境之间相互作用的一门交叉学科.近数十年来,中国山地环境气象研究进展迅速.1960年以来,大气物理研究所多次参加中国科学院组织的山地综合科学考察,多学科的相互交叉促进了中国山地环境气象的研究,特别是在珠穆朗玛峰、天山托木尔峰和横断山脉山地环境气象、雅鲁藏布大峡谷环境气象研究等方面进展较快.为监测全球环境气象变化,中国气象局在青藏高原上设立了环境气象监测站.此外,在利用臭氧卫星资料研究青藏高原与臭氧分布、准两年振荡(QBO)信号、ENSO信号的关系方面也颇有进展.     

Climate observation of the Three Gorges Region of the Yangtze River in 2019

2019年,长江三峡地区年平均气温17.5℃,较常年偏高0.3℃;冬季偏冷,春,夏,秋三季气温均偏高;年高温日数偏多.2019年三峡地区年降水量1035.1毫米,较常年偏少13％;四季降水均偏少;年暴雨日数偏少.2019年,长江三峡地区年平均风速较常年偏大;年平均相对湿度接近常年;酸雨强度弱,为1999年以来的最弱年,...     

Carbon dioxide, methane, and nitrous oxide emissions from a rice-wheat rotation as affected by crop residue incorporation and temperature

Field measurements were made from June 2001 to May 2002 to evaluate the effect of crop residue application and temperature on CO2, CH4, and N2O emissions within an entire rice-wheat rotation season.Rapeseed cake and wheat straw were incorporated into the soil at a rate of 2.25 t hm-2 when the rice crop was transplanted in June 2001. Compared with the control, the incorporation of rapeseed cake enhanced the emissions of CO2, CH4, and N2O in the rice-growing season by 12.3%, 252.3%, and 17.5%,respectively, while no further effect was held on the emissions of CO2 and N2O in the following wheatgrowing season. The incorporation of wheat straw enhanced the emissions of CO2 and CH4 by 7.1%and 249.6%, respectively, but reduced the N2O emission by 18.8% in the rice-growing season. Significant reductions of 17.8% for the CO2 and of 12.9% for the N2O emission were observed in the following wheatgrowing season. A positive correlation existed between the emissions of N2O and CO2 (R2 = 0.445, n =73, p ＜ 0.001) from the rice-growing season when N2O was emitted. A trade-off relationship between the emissions of CH4 and N2O was found in the rice-growing season. The CH4 emission was significantly correlated with the CO2 emission for the period from rice transplantation to field drainage, but not for the entire rice-growing season. In addition, air temperature was found to regulate the CO2 emissions from the non-waterlogged period over the entire rice-wheat rotation season and the N2O emissions from the nonwaterlogged period of the rice-growing season, which can be quantitatively described by an exponential function. The temperature coefficient (Q10) was then evaluated to be 2.3±0.2 for the CO2 emission and 3.9±0.4 for the N2O emission, respectively.     

基于遥感与GIS集成的土壤墒情监测服务系统

遥感与GIS集成土壤墒情监测服务系统运行于Windows平台,基于遥感与GIS集成技术,利用热惯量法、植被缺水指数法、植被温度条件指数法和单时相资料回归法等多种模式计算土壤含水量。在遥感监测与墒情分析中考虑背景地理信息的影响,提高了遥感墒情监测的精度和服务水平。该系统具有多种墒情模式计算、图像显示、图像叠加、统计分析、模板处理和输出等功能。应用该系统得出的2005年4月河南省遥感墒情分布图和干旱面积与实测结果基本一致。     

福建省夏季高温成因分析

通过对1961－1999年7－9月各高温过程环境背景的统计分析，探讨造成福建省高温天气的主要天气系统及形势特征。结果表明：（1）夏季高温过程分布具有较为明显的空性和时间性；（2）西太平副热带高压是影响福建省高温过程的主要天气系统；（3）热带系统外围西北风场控制下的显著增温现象是影响高温过程的重要天气系统；（4）地形作用一定程度上影响着气温的空间分布。     

金星探测研究进展与未来展望

金星探测是解答太阳系类地行星形成演化,地球宜居性的形成和未来发展,以及外太阳系宜居星球搜索策略的关键。由于金星恶劣的环境条件、对探测技术的多重挑战和相对高昂的探测成本,金星探测和研究程度远不及月球和火星。自20世纪90年代后期,金星探测任务相对匮乏。本文梳理了国际上金星探测研究进展、关键科学问题及技术需求,提出了未来金星的探测目标和探测方式建议。目前,对金星大气和气候研究程度最高,包括大气结构和大气化学,能量平衡和热结构,云层和霾层,大气环流和动力学以及气候演化等。高层大气的物理化学和太阳风与金星的相互作用方面也有重要进展。金星地表和内部的研究则相对滞后,研究涵盖金星表面形貌特征,撞击和重塑历史,火山和构造活动,地表物质组成,地表和大气相互作用等,但受限于数据的空间覆盖率和较低的分辨率和精度,诸多重大问题尚未解答,迫切需要新的探测数据。除探测任务外,金星研究还依赖于地基观测、实验室模拟和数值模拟研究。地面模拟设施对支持金星探测任务研发和金星基础科学研究尤为重要。未来十年是中国开展金星探测的契机和研发相关技术的关键时期。本文可为对金星探测、行星科学、太阳系探测感兴趣的科学家和工程人员提供...