黑河地区绿州和沙漠地面辐射收支的若干特征   总被引：10，自引：3，他引：7  

季国良马晓燕  邹基玲吕兰芝 《干旱气象》2003,21(3):29-33

利用HEIFE中在绿州和沙漠两个测站所取得的资料。分析了两种不同下垫面辐射收支及其季节变化特征。结果表明：绿州区地表反射率明显小于沙漠区,季节变化明显;地面向上长波辐射绿州小于沙漠,地面有效辐射绿州小于沙漠。且季节变化明显;地表净辐射绿州大于沙漠,其能量以潜热为主输入大气;干旱地区的绿州光合有效辐射年总量大于河北、山声等地。光合有效辐射资源极为丰富。  相似文献   

行星反照率的取值和假设的讨论     

林振山 《热带气象学报》2002,18(4):424-427

首先分析了Wang的有关行星反照率假设的错误之处,而后分别对Budyko、North的行星反照率假设提出修改方案,最后提出了有关行星反照率的非线性分段、反馈假设:  相似文献   

Millennial‐scale variability in the oceans: an ocean modelling view     

Grant R. Bigg  Martin R. Wadley 《第四纪科学杂志》2001,16(4):309-319

Climate and ocean‐only models have shown that the ocean will respond abruptly to significant perturbations in surface forcing. Centennial‐scale oscillation is a characteristic of circulation in large semi‐enclosed ocean basins such as the Arctic, whereas millennial‐scale adjustment to changes in surface forcing has been found in the global ocean component of climate models. We show that the millennial time‐scale in climate models is likely to be intrinsic to the ocean through its presence in an ocean‐only model. The strength of the thermohaline circulation is shown to be very sensitive to the magnitude of ice albedo and, to a lesser extent, perturbation in the surface freshwater flux. Modelled glacial ocean circulation, in contrast to present‐day simulations, requires an enhanced freshwater flux over the northern Atlantic, even in its non‐Heinrich state, to obtain realistic overturning in the North Atlantic. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

黄河三角洲地表特征参数的遥感研究   总被引：5，自引：0，他引：5  

张长春  王晓燕  崔亚莉  邵景力 《水文地质工程地质》2005,32(2):71-75

地表特征参数与下垫面特征密切相关,它是研究地表物质平衡和能量平衡的基础,因而应用遥感方法反演区域地表特征参数日益受到重视。本文主要应用现有的地表特征参数遥感反演模型,利用AVHRR和TM数据反演了黄河三角洲的地表特征参数:地表反照率、地面温度和植被指数等,并根据反演结果研究了地表特征参数及其合理组合所反映的地表特征。农田植被和天然植被的植被指数变化规律不同;在植被全覆盖区域,植被指数与反照率成幂函数关系,在极干或极湿情况下,地表温度与反照率成线性关系;地表特征参数的合理组合反映出黄河三角洲下垫面覆盖度低,裸地较多,地表较湿润,蒸发量较大。  相似文献   

沙尘气溶胶卫星遥感现状与需要关注的若干问题   总被引：5，自引：2，他引：3  

张鹏  王春姣  陈林  白文广  漆成莉  齐瑾 《气象》2018,44(6):725-736

沙尘暴是全球干旱、半干旱地区特有的一种灾害性天气,所产生的沙尘气溶胶是全球气溶胶系统重要组成部分,对全球环境、天气、气候和生态有复杂的影响。沙尘气溶胶作为一种吸收性气溶胶,对太阳辐射有着较强的吸收,还能通过加热大气、改变大气稳定度、蒸发云滴、减少云量等"半直接方式"影响气候。卫星遥感对沙尘气溶胶的监测具有独特的优势,是全球沙尘研究的重要手段。本文系统整理和介绍了目前常用的可见近红外、热红外、被动微波、紫外和主动激光测量等五类卫星遥感沙尘气溶胶的主要方法,在总结典型遥感仪器和主要产品基础上,讨论了遥感产品的定量精度和地面验证问题,结合辐射传输理论模拟了可见近红外和热红外的卫星观测,探讨了可见近红外遥感的地表反照率影响和热红外高光谱遥感的波段选择问题,最后对未来的一些研究重点进行了展望。  相似文献   

Aerosol Direct Radiative Forcing over Shandong Peninsula in East Asia from 2004 to 2011          下载免费PDF全文

XIN Jin-Yuan  ZHANG Qing  GONG Chong-Shui  WANG Yue-Si  DU Wu-Peng  ZHAO Yong-Fang 《大气和海洋科学快报》2014,(1):74-79

Recent vigorous industrialization and urbanization in Shandong Peninsula,China,have resulted in the emission of heavy anthropogenic aerosols over the region.The annual means of aerosol optical depth（AOD）,Angstrom exponent（α）,single-scattering albedo（SSA）,aerosol direct radiative forcing（ARF）,surface radiative forcing（SRF）,and top-of-the atmospheric radiative forcing（TOA） recorded during 2004–2011 were respectively 0.67±0.19,1.25±0.24,0.93±0.03,47±9 W m^-2,-61±9 W m^-2,and-14±8 W m^-2.The aerosol optical properties and ARF characteristics showed remarkable seasonal variations due to cycle changes in the aerosol components and dominance type.The atmosphere-surface system was cooled by ARF in all years of the study due to anthropogenic sulfate and nitrate emission and sea salt aerosols.The magnitude of TOA cooling was larger in summer（-15±17 W m^-2） and autumn（-12±7 W m^-2） than that in spring（-8±4 W m^-2） and winter（-9±10 W m^-2）.  相似文献   

敦煌荒漠戈壁地区裸土地表反照率参数化研究   总被引：4，自引：1，他引：3  

郑志远  韦志刚  李振朝  魏红  刘慧 《大气科学》2014,38(2):297-308

利用敦煌站观测资料,选取其中观测资料完整且连续性好的7个年份每年5～10月的地表净辐射四分量和土壤湿度资料,分析研究了敦煌荒漠戈壁地区裸土地表反照率与太阳高度角和表层土壤含水量之间的关系,结果表明:地表反照率与太阳高度角呈e指数关系,随太阳高度角的增大而减小,当太阳高度角大于40°时,地表反照率趋于稳定。表层土壤含水量的增大可导致地表反照率的减小,地表反照率与5 cm深土壤湿度呈线性关系。另外,建立了敦煌荒漠戈壁地区裸土地表反照率与太阳高度角和表层土壤含水量之间的双因子参数化公式,提出了一种更加适合该地区的地表反照率参数方案,并且选取2002年6～9月的实测资料对拟合的参数化公式进行模拟验证。本文所提出的地表反照率参数化方案能够很好地再现该地区裸土地表反照率的“U”型日变化特征,可准确地模拟出地表反照率的动态变化趋势。基于此参数化方案计算得到的地表反射辐射与实测值基本一致。  相似文献   

植被地表反照率动态模拟方法比较-以玉米农田为例     

蔡福  明惠青  赵先丽  米娜  梁涛  刘明  宋国云  陈雨  张玉书 《气象与环境学报》2014,30(5):78-82

利用2007年锦州玉米农田生态系统野外观测站玉米生长季辐射资料,对地表反照率综合模型、半经验双层模型和简化双层模型模拟精度进行比较。结果表明：简化双层模型在玉米生育初期模拟能力较差,其他时段模拟能力都较强,尤其在玉米生育后期更为明显;半经验双层模型除在玉米叶面积指数处于最大时期模拟误差较小外,其他时段基本无法模拟。综合模型大部分时段模拟能力都较强,仅在玉米生育后期模拟能力稍差,该模型对实现玉米农田地表反照率动态参数化更为理想,可为改进陆面过程模型提供参考。  相似文献   

融合Landsat ETM+和MODIS数据估算高时空分辨率地表短波反照率   总被引：2，自引：0，他引：2  

张开  周红敏  王锦地  薛华柱 《遥感学报》2014,18(3):497-517

提出一种通过融合高空间低时间分辨率、低空间高时间分辨率地表短波反照率,来估算高时空分辨率地表短波反照率的方法。首先,利用Landsat ETM+数据,通过窄波段到宽波段的转换得到一景或多景空间分辨率较高的ETM+蓝天空短波反照率;然后,在MODIS短波反照率产品基础上,以天空光比例因子为权重,得到空间分辨率较低的MODIS蓝天空短波反照率;最后,利用STARFM(Spatial and Temporal Adaptive Reflectance Fusion Model)模型融合ETM+短波反照率的空间变化信息和MODIS短波反照率的时间变化信息,得到高时空分辨率的地表短波反照率。针对STARFM模型在异质性区域估算精度降低的问题,通过以MODIS反照率影像各像元的端元(各地类)反照率取代MODIS像元反照率来提取时空变化等信息参与STARFM模型的融合过程,达到提高异质性区域估算精度的目的。结果显示,直接利用STARFM模型估算得到的高空间分辨率地表短波反照率处在合理的精度范围内(RMSE0.02),用改进后的STARFM模型估算得到的异质性区域短波反照率和真实ETM+短波反照率间的相关系数增大。  相似文献   

Comprehensive study on the influence of evapotranspiration and albedo on surface temperature related to changes in the leaf area index     

Jiawen Zhu  Xiaodong Zeng 《大气科学进展》2015,32(7):935-942

Many studies have investigated the influence of evapotranspiration and albedo and emphasize their separate effects but ignore their interactive influences by changing vegetation status in large amplitudes. This paper focuses on the comprehensive influence of evapotranspiration and albedo on surface temperature by changing the leaf area index(LAI) between 30–90 N.Two LAI datasets with seasonally different amplitudes of vegetation change between 30–90N were used in the simulations.Seasonal differences between the results of the simulations are compared, and the major findings are as follows.(1) The interactive effects of evapotranspiration and albedo on surface temperature were different over different regions during three seasons [March–April–May(MAM), June–July–August(JJA), and September–October–November(SON)], i.e., they were always the same over the southeastern United States during these three seasons but were opposite over most regions between30–90 N during JJA.(2) Either evapotranspiration or albedo tended to be dominant over different areas and during different seasons. For example, evapotranspiration dominated almost all regions between 30–90N during JJA, whereas albedo played a dominant role over northwestern Eurasia during MAM and over central Eurasia during SON.(3) The response of evapotranspiration and albedo to an increase in LAI with different ranges showed different paces and signals. With relatively small amplitudes of increased LAI, the rate of the relative increase in evapotranspiration was quick, and positive changes happened in albedo. But both relative changes in evapotranspiration and albedo tended to be gentle, and the ratio of negative changes of albedo increased with relatively large increased amplitudes of LAI.  相似文献