黄土高原冬小麦地膜复盖的农业气象效应的研究   总被引：1，自引：0，他引：1  

裴步祥  毛飞  李德广  赵同应  刘占贞  胡良温 《气象学报》1991,49(4):569-573

地膜复盖是60年代国外农业生产中的一项新技术。它可以有效地改善作物地段的土壤水分和热量状况,有利于作物的生长发育和产量的提高。在我国逐步推广使用,取得了较好的结果。本文利用山西省两试验点,在1987—1988年冬小麦生长季进行复膜试验的资料,系统地分析了其农业气象效应。试验结果表明,黄土高原高海拔地区复膜栽培冬小麦是提高其产量的有效措施。  相似文献   

Validation of the Atmospheric Infrared Sounder Retrieval Products over China and Their Application in Numerical Mode          下载免费PDF全文

GAO Wenhu  ZHAO Fengsheng  GAI Changsong 《Acta Meteorologica Sinica》2007,21(2):141-152

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.  相似文献   

Effect of NO2 in exhaust gas from an oxyfuel combustion system on the cap rock of a proposed CO2 injection site     

《Applied Geochemistry》2016

A laboratory geochemical study was conducted using a drill core sample of cap rock from the Surat Basin, Australia, to investigate the effect of NO₂ contained in the CO₂ gas exhausted from the oxyfuel combustion process (oxyfuel combustion CO₂) on the cap rock. A gas (CO₂ containing NO₂) was prepared to simulate the exhaust gas produced from the oxyfuel combustion process. Two types of gases (pure CO₂ and CO₂ containing SO₂) were also prepared as reference gases. The effect of NO₂ on cap rock was studied experimentally using these gases. No differences in the amounts of leached ions and pH changes for CO₂ containing NO₂ (36 ppmv), pure CO₂, and CO₂ containing SO₂ (35 ppmv) existed. The pH values decreased immediately after CO₂ gas injection but increased with time as a result of mineral buffering. Leaching of Fe, Mg, Ca, and K was suggested to have occurred as the result of dissolution of Fe-chlorite, prehnite and illite-smectite mixed layer clay in the shale sample. The amounts of Ca, Fe, and Mg leached with CO₂ containing NO₂ (318 ppmv) were higher than those for pure CO₂. For the mixture containing 318 ppmv NO₂, the pH increased more than that for the other gas conditions immediately after the pH fall at the start of the experiment, because oxidation-reduction reactions occurred between Fe²⁺ and NO₃⁻. Moreover, the results indicated that some of the leached Ca and Fe were deposited on the shale sample because of the pH increase. Therefore, we concluded that the effects of NO₂ on mineral dissolution and pH changes of formation water are negligible when oxyfuel combustion CO₂ containing about 30 ppmv of NO₂ is injected into an underground aquifer. In addition, even if about 300 ppmv NO₂ is accidentally injected into the underground aquifer, mineral dissolution is suppressed due to the buffering of pH decrease after gas injection.  相似文献   

Particulate matter trends and quantification of the spring sand-dust contribution in Hohhot,Inner Mongolia,from 2013 to 2017          下载免费PDF全文

Wenkang Gao  Lingyun Zhu  Zhanyun Ma  Qingxian Gao  Xuepu Yu  Sufen Wu  Yu Gu 《大气和海洋科学快报》2021,14(2):81-86

2013年9月国务院颁布了《大气污染防治行动计划》.研究其实施前后呼和浩特市大气污染物浓度变化及及原因;同时,分析了春季沙尘天气对于呼和浩特市大气环境颗粒物浓度的定量影响.结果表明:呼和浩特市大气环境质量持续改善,但大气污染物浓度仍然较高.PM2.5和PM10年均浓度分别超过国家二级标准22.9％和35.7％;2013-2017年春季PM2.5和PM10浓度降幅较大,沙尘天气对呼和浩特市PM2.5,PM10,和TSP浓度的绝对贡献范围分别在0.6-5.2μg m-3,9.0-16.9 μg m-3和 14.7-30.0 μg m-3.  相似文献   

渭南市高炮火箭人工增雨作业分析          下载免费PDF全文

张丽娟  李秀琳  刘瑜 《山西气象》2006,(2):24-26

利用1954年～2003年的气象要素建立气象信息数据库,对冬小麦不同生长期的生长状况和气象因子建立相关关系,从而建立规则库,最终应用Vb建立操作服务平台。系统投入业务运行以来效果良好,提高了服务的客观性和及时性。  相似文献   

Analysis of quantitative precipitation forecasts using the Dynamic State Index     

《Atmospheric Research》2010,95(4):694-703

The German Weather Service (DWD) has two non-hydrostatic operational weather prediction models with different spatial resolution and precipitation parametrisations. The coarser COSMO-EU model has a spatial resolution of 7 km, whereas the higher-resolution COSMO-DE model has a gridspace of 2.8 km and explicitly resolves deep convection. To improve the numerical weather prediction (NWP) models it is necessary to understand precipitation processes. A central goal is the statistical evaluation of precipitation forecasts with dynamic parameters. Here, the Dynamic State Index (DSI) is used as a dynamic threshold parameter. The DSI theoretically describes the change of atmospheric flow fields as deviations from a stationary adiabatic solution of the primitive equations (Névir, 2004). For seasonal area means the DSI shows a remarkably high correlation with the precipitation forecasts provided by the COSMO-DE model. This is especially the case for the summer of 2007. The same analysis has been performed with the COSMO-EU forecast data and the results were compared with those from the COSMO-DE model. Moreover, an independent precipitation analysis, with a resolution corresponding to 7 km and 2.8 km, has been compared with respect to modelled precipitation and the DSI. In addition, correlations between the DSI and modelled as well as observed precipitation as a function of the forecast time for the different grid resolutions are also presented. The results show, that after 12 h, the correlation of the persistence forecast with the DSI reaches two thirds of the initial value. Thus, the DSI offers itself as a new dynamic forecast tool for precipitation events.  相似文献   

Latitudinal dependence of the dry air effect on tropical cyclone development     

《Dynamics of Atmospheres and Oceans》2019

The impacts of dry air on tropical cyclone (TC) development at different latitudes with no mean flows are investigated with idealized simulations. It is found that the effective radius of the dry air is sensitive to its vertical distribution and the background earth rotation. The effect of low-level dry-air layer in inhibiting TC development decreases with increasing latitude. At lower latitudes, the greater boundary layer gradient wind imbalance results in a strong low-level inflow, and the dry air can easily penetrate into the TC inner-core region. The intruding dry air inhibits the inner-core deep convection and leads to marked asymmetric convective structure, which significantly suppresses TC development. In contrast, at higher latitudes, the dry air gets moistened before reaching the TC inner-core region due to a weaker radial inflow but can suppress the development of the outer spiral rainbands. The suppressed outer spiral rainbands lead to a weaker barrier effect to the boundary layer inflow and help TC development. Furthermore, the lower the altitude of dry-air layer resides, the greater the impact on TC intensification. The low-level pathway associated with the boundary layer inflow plays an important role on how dry-air layer acts on a TC without considering the mean flow effects. Through examining the climatological distribution of the moisture field, we expect that the intrusion of dry air can be more frequent in the North Atlantic area and therefore has more effects on TC development than in the western North Pacific.  相似文献   

祁连山近45 a年降水异常的气候特征   总被引：3，自引：2，他引：1  

张小明  魏锋  陆燕 《干旱气象》2006,24(3):35-41

利用祁连山地区17个测站1960~2004逐日降水资料,统计逐年不同量级的雨日数及年降水量,对年总降水量标准化后进行经验正交展开(EOF)和旋转经验正交展开(REOF),研究其异常的空间结构及时间演变规律。结果表明,祁连山地区年降水与不同量级雨日数的气候平均分布具有地理分布上的相似性。无论年降水还是不同量级的雨日数,同纬度地区西侧明显多于东侧,祁连山东段多于西段,等值线呈西北—东南走向。年降水异常在空间上主要表现为整体一致的变化特点,其次表现为东西相反的变化趋势。旋转载荷向量场(RLV)反映出4个异常型,即祁连山西段北坡区、祁连山东段区、祁连山中西段南坡区,祁连山中段北坡区。近45 a,祁连山西段北坡区年代际变化幅度明显,其他各区年代际变化幅度相对较小。小波分析发现,各区年降水周期变化并不一致,体现出祁连山地区年总降水的复杂性。  相似文献   

秦巴谷地夏季降水的时空特征分析     

朱梅  肖天贵  余兴  徐小红 《气象科技》2014,42(4):663-670

利用安康和汉中地区21个测站1963—2012年逐日降水和气温资料以及统计诊断方法,分析了秦巴谷地年均气温和降水以及季节降水的时空变化特征,结果表明:秦巴谷地的年均气温呈明显线性增暖趋势,而年降水量的线性变化趋势不明显;在降水量较为集中的春夏秋3季中,春秋季降水量呈减小的趋势,而夏季的降水量却呈增多的趋势,尤其是近10年来降水量增多趋势明显。利用REOF方法将秦巴谷地夏季降水量分解为3个主要空间模态,即西部、东部和中部型,其中西部型和东部型是秦巴谷地夏季降水分布最敏感的区域类型。对秦巴山区2010年7月17—18日一次典型强降水天气过程的分析表明,西部型和东部型可能是秦巴地区的主要典型降雨型,对于秦巴地区降水规律认识和天气预报及防灾减灾有着重要意义。  相似文献   

近41年中国不同季节降水气候分区及趋势   总被引：16，自引：7，他引：9  

秦爱民  钱维宏 《高原气象》2006,25(3):495-502

利用中国486个测站1960—2000年逐日降水观测资料,采用分层聚类和相似分析方法,兼顾降水的年内季节变化和年际变化,对中国降水进行了气候区划。利用动态分析分层聚类过程中组内和组间平均相关系数的差异指标法,为不同季节降水研究找到了适合的分区方案。在年降水分区方案中,得到中国降水的三级气候分区:11区、28区和54区。用同样的方法得到各月、季降水的分区方案。在分析过程中发现:在同样相似条件下,夏季(及夏季各月)分区数明显多于其它季(月);11个Ⅰ级分区年降水具有明显的区域性特征。分析结果在一定程度上说明了所用分区方法的客观性。  相似文献