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1.
Weng Duming 《Acta Meteorologica Sinica》1995,9(2):228-236
ERBE and ISCCP data are used to investigate the cloud forcing and latitude and atmospheric temperature effects on outgoing longwave radiation(OLR) in the earth-atmosphere system,and the similarity of OLR field to 500 hPa and surface effective radiation fields.Also,discussion is taken up of the OLR distribution on a nationwide basis,indicating that the winter(summer) OLR pattern is roughly a zonal type(asymmetrical saddle) with the annual pattern analogous to the January one.In the end the yearly OLR variation features are addressed on a regional basis. 相似文献
2.
中国地—气系统长波射出辐射（OLR）的气候特征 总被引：1，自引：0，他引：1
根据ERBE和ISCCP资料讨论了云对地—气系统长波射出辐射（OLR）的强迫作用及纬度、大气温度等因子的影响。分析了OLR场与500hPa及地表有效辐射场的相似问题。阐述了OLR在全国的分布特征，指出冬季OLR场大致呈纬向型．夏季为一不对称的鞍形场。年分布与1月的相似。最后还就各区域的OLR年变化特征进行了讨论． 相似文献
3.
根据美国NOAA卫星观测得到的射出长波辐射资料(Outgoing Longwave Radiation,简称OLR)，分析了西藏高原及其附近地区各月的辐射气候特征，指出:高原冬、春季节OLR主要反映了高原下垫面温度的季节变化，高原夏季为雨季，OLR与降水之间存在较好的负相关。印度季风爆发前后的OLR演变特征反映出中、低纬大气环流调整对高原雨季形成及降水分布的影响。旱涝年OLR合成分析表明:高原夏季降水与赤道印度洋反Walker环流强弱、印度季风槽、副热带高压及西太平洋暖池区对流强度、位置变化有密切的关系。 相似文献
4.
本文利用NOAA13年月平均格点资料分析了冬夏热带副热带射出长波辐射(OLR)的气候特征及其遥相关结构。结果表明,OLR场的高低值带有明显的季节变动,低值带中心从冬至夏由赤道西太平洋地区向西北移至孟加拉湾,高值带从冬至夏北移约10—15个纬度,但东南太平洋高值区的位置无明显季节变动。 遥相关结构分析表明,冬夏季节OLR场分别有8个遥相关关键区,它们之间存在着较强的同时性遥相关联系。冬季遥相关型主要由位于赤道低纬度“印度洋—西太平洋—东太平洋—大西洋”的纬向2波式遥相关和在太平洋中部、东亚地区,南北半球副热带与赤道地区的经向负遥相关型组成。夏季OLR遥相关关键区主要分布在孟加拉湾至赤道西太平洋、东太平洋与低纬度大西洋和中纬度东亚沿海与北美大陆,构成低纬度和中纬度两类纬向正遥相关型。进一步分析发现,冬夏OLR遥相关型的年际变化较好地揭示了OLR场异常与ENSO、低纬度Walker、Hadley环流等海—气系统异常的整体联系。 相似文献
5.
Using daily outgoing long-wave radiation （OLR） data from the National Oceanic and Atmospheric Administration （NOAA） and the National Center for Environmental Prediction/National Center for Atmospheric Research （NCEP/NCAR） reanalysis data of geopotential height fields for 1979-2006, the relationship between persistent heavy rain events （PHREs） in the Huaihe River valley （HRV） and the distribution pattern of convective activity in the tropical western Pacific warm pool （WPWP） is investigated. Based on nine cases of PHREs in the HRV, common characteristics of the West Pacific subtropical high （WPSH） show that the northern edge of the WPSH continues to lie in the HRV and is associated with the persistent ＂north weak south strong＂ distribution pattern of convective activities in the WPWP. Composite analysis of OLR leading the circulation indicates that the response of the WPSH to OLR anomaly patterns lags by about 1-2 days. In order to explain the reason for the effects of the distribution pattern of convective activities in the WPWP on the persistent northern edge of the WPSH in the HRV, four typical persistent heavy and light rain events in the Yangtze River valley （YRV） are contrasted with the PHREs in the HRV. The comparison indicates that when the distribution pattern of the convective activities anomaly behaves in a weak （strong） manner across the whole WPWP, persistent heavy （light） rain tends to occur in the YRV. When the distribution pattern of the convective activities anomaly behaves according to the ＂north weak south strong＂ pattern in the WPWP, persistent heavy rain tends to occur in the HRV. The effects of the ＂north weak south strong＂ distribution pattern of convective activities on PHREs in the HRV are not obvious over the seasonal mean timescale, perhaps due to the non-extreme status of convective activities in the WPWP. 相似文献
6.
长序列卫星辐射资料的缺乏一直是制约青藏高原(以下简称高原)辐射长期变化研究的重要原因之一。对国际上最新提供的1984—2017年ISCCP-FH(以下简称FH)长序列卫星辐射资料中的大气顶逸出长波辐射(OLR)、到达地面短波辐射(SWD)、地面向上长波辐射(LWU)、到达地面长波辐射(LWD)进行分析,评估了FH辐射资料在全天气条件下的青藏高原地区的适用性。结果表明:与观测相比,FH资料的4种辐射通量气候平均值误差均小于5%,其中OLR和SWD的偏差较小,LWU的偏差最大。FH资料能正确反映高原各辐射通量的冬季增强趋势,OLR和LWD在各季节的长期变化趋势均与观测一致,LWU则呈现虚假的减弱趋势。总体来说,在高原地区,FH资料的地面短波辐射通量比长波辐射通量适用性好。进一步对长波辐射偏差原因分析显示,气温偏差会增强LWD的气候态和长期趋势,而地温偏差对LWU的作用与之相反。辐射模型、云和水汽的差异导致最终FH资料中的LWD气候态和长期趋势较观测略偏弱,FH资料的计算方案在一定程度上修正了地温偏差造成的LWU偏弱。研究结果将为使用FH辐射资料提供参考依据。 相似文献
7.
8.
The NOAA daily outgoing longwave radiation (OLR) and the Global
Precipitation Climatology Project （GPCP） daily precipitation data are used
to study the variation of dominant convection modes and their relationships
over Asia, the Indian Ocean, and the western Pacific Ocean during the
summers from 1997 to 2004. Major findings are as follows: (1) Regression
analysis with the OLR indicates the convective variations over Asian monsoon
region are more closely associated with the convective activities over the
western subtropical Pacific (WSP) than with those over the northern tropical
Indian Ocean (NTIO). (2) The EOF analysis of OLR indicates the first mode
(EOF1) exhibits the out-of-phase variations between eastern China and India,
and between eastern China and the WSP. The OLR EOF1 primarily exhibits
seasonal and even longer-term variations. (3) The OLR EOF2 mostly displays
in-phase convective variations over India, the Bay of Bengal, and
southeastern China. A wavelet analysis reveals intraseasonal variation (ISV)
features in 2000, 2001, 2002, and 2004. However, the effective ISV does not
take place in every year and it seems to occur only when the centers of an
east--west oriented dipole reach enough intensity over the tropical Indian
and western Pacific Oceans. (4) The spatial patterns of OLR EOF3 are more
complicated than those of EOF1 and EOF2, and an effective ISV is noted from
1999 to 2004. The OLR EOF3 implies there is added complexity of the OLR
pattern when the effective ISV occurs. (5) The correlation analysis suggests
the precipitation over India is more closely associated with the ISV,
seasonal variations, and even longer-term variations than precipitation
occurring over eastern China. 相似文献
9.
为了探索热带地区出射长波辐射（OLR）的内在变化规律,利用去趋势波动分析（DFA）方法,对整个热带地区（0~357.5 °E,22.5 °S~22.5 °N）1979—2013年NOAA逐日的OLR资料进行分析。研究结果表明:整个热带地区的OLR存在幂律相关,其标度指数值主要集中在0.65~0.72之间,具有较好的长程相关性（或持续性）。西太平洋、刚果盆地和南美洲因对流发展旺盛,导致上空高云量偏大,OLR值主要取决于云顶温度和云量,而云本身变化较快,使得该地区OLR表现出较弱的长程持续性;中东太平洋、大西洋和撒哈拉沙漠地区上空高云量偏少,OLR值主要取决于海表或陆表的温度,而海表或陆表温度变化相对比较缓慢,使得该地区OLR表现出较强的长程持续性。此外,通过随机打乱逐日OLR时间序列去除趋势和相关性,进一步验证了热带地区OLR的长程持续性是由时间序列的分形特征造成的。 相似文献
10.
Intraseasonal variability in subtropical South America as depicted by precipitation data 总被引：1，自引：1，他引：0
Daily precipitation data from three stations in subtropical Argentina are used to describe intraseasonal variability (20–90 days) during the austral summer. This variability is compared locally and regionally with that present in outgoing longwave radiation (OLR) data, in order to evaluate the performance of this variable as a proxy for convection in the region. The influence of the intraseasonal activity of the South American Seesaw (SASS) leading convection pattern on precipitation is also explored. Results show that intraseasonal variability explains a significant portion of summer precipitation variance, with a clear maximum in the vicinity of the SASS subtropical center. Correlation analysis reveals that OLR can explain only a small portion of daily precipitation variability, implying that it does not constitute a proper proxy for precipitation on daily timescales. On intraseasonal timescales, though, OLR is able to reproduce the main features of precipitation variability. The dynamical conditions that promote the development of intraseasonal variability in the region are further analyzed for selected summers. Seasons associated with a strong intraseasonal signal in precipitation variability show distinctive wet/dry intraseasonal periods in daily raw data, and are associated with a well defined SASS-like spatial pattern of convection. During these summers, strong large-scale forcing (such as warm El Niño/Southern Oscillation (ENSO) events and/or tropical intraseasonal convective activity), and Rossby-wave-like circulation anomalies extending across the Pacific Ocean, are also observed. 相似文献
11.
Eui-Seok Chung Byung-Ju Sohn Johannes Schmetz 《Meteorology and Atmospheric Physics》2009,105(3-4):109-119
Diurnal variations of outgoing longwave radiation (OLR) are examined in conjunction with diurnal variations of high cloud and upper tropospheric humidity (UTH) over the Indian Ocean and surrounding land areas using Meteosat-5 measurements. Most land areas exhibit a significant diurnal variation of OLR with the largest amplitude over the Arabian Peninsula, whereas the diurnal variation of OLR is much weaker over the Indian Ocean. While diurnal maxima of OLR are found in the early afternoon over many regions of the analysis domain following the diurnal cycle of solar heating, convectively active regions of both land and ocean where high cloud and UTH exhibit distinct diurnal variations show OLR maxima before local noon. These results indicate that high cloud development in the afternoon induces a shift in local time of OLR maxima over convective regions. In agreement with earlier studies it is shown that UTH diurnal variations are less important in regard to their impact on the OLR variations. 相似文献
12.
Investigated are effects of the total cloudiness and other factors on earth-atmosphere net radiation(EANR) and analyzed is its relation to other components and ground surface net radiation in the context of ERBE and ISCCP.Evidence suggests that planetary scale albedo and earth-atmosphere short wave absorption radiation have maximum effect on the net radiation under study,with the influence of cloud and latitude displayed predominantly through the two factors;OLR has relatively weak effect;the earth-atmosphere net radiation is well correlated with surface net radiation.Analysis is also performed of the geographic distribution of the earth-atmosphere net radiation throughout China,and the annual curve of the net radiation on a local basis is marked by high(low) value in summer(winter) with the impact of factors.including total cloudiness responsible largely for the shift of the months with maximum. 相似文献
13.
Investigated are effects of the total cloudiness and other factors on earth-atmosphere net radia-tion(EANR)and analyzed is its relation to other components and ground surface net radiation inthe context of ERBE and ISCCP.Evidence suggests that planetary scale albedo and earth-atmo-sphere short wave absorption radiation have maximum effect on the net radiation under study,withthe influence of cloud and latitude displayed predominantly through the two factors;OLR has rela-tively weak effect;the earth-atmosphere net radiation is well correlated with surface net radiation.Analysis is also performed of the geographic distribution of the earth-atmosphere net radiationthroughout China,and the annual curve of the net radiation on a local basis is marked by high(low)value in summer(winter)with the impact of factors.including total cloudiness responsiblelargely for the shift of the months with maximum. 相似文献
14.
Summary Climatic determinants of summer (Nov-Mar) rainfall over southern Africa are investigated through analysis of sea surface temperatures (SST), outgoing longwage radiation (OLR) and tropospheric wind with respect to the Southern Oscillation Index (SOI) and the stratospheric quasi-biennial oscillation (QBO). Index-to-field correlation maps are presented at various lags for the austral spring and summer seasons to establish the spatial dependence and evolution of coherent, statistically significant features. The SOI signal is reflected in upper-level zonal wind anomalies over the equatorial Atlantic Ocean during spring. SSTs in the central Indian Ocean are significantly negatively correlated with the SOI in summer. On the other hand, OLR correlations are weak over southern Africa in the summer, implying that the SOI signal may not dominate interannual convective variability.QBO correlations with SST are relatively weak, but with 200 hPa zonal winds over the western equatorial Ocean, positive correlations are noted. A standing wave pattern is described in the sub-tropics. The OLR correlation pattern represents a dipole with increased convection over eastern and southern Africa in contrast to reduced convection over Madagascar when the QBO is in west phase.Contingency analyses indicate that the global indices are unreliable predictors in isolation. However the characteristics and domain of influence of SOI and QBO signals are identified and may offer useful inputs to objective multivariate models for different modes of southern African rainfall variability.With 12 Figures 相似文献
15.
C. V. Singh 《Meteorology and Atmospheric Physics》2004,85(4):227-234
Summary The present study involves the use of Empirical Orthogonal Function (EOF) analysis/Principal Component Analysis (PCA) to compare the dominant rainfall patterns from normal rainfall records over India, coupled with the major modes of the Outgoing Long-wave Radiation (OLR) data for the period (1979–1988) during the monsoon period (June–September). To understand the intraseasonal and interannual variability of the monsoon rainfall, daily and seasonal anomalies have been obtained by using the (EOF) analysis. Importantly, pattern characteristics of seasonal monsoon rainfall covering 68 stations in India are highlighted.The purpose is to ascertain the nature of rainfall distribution over the Indian continent. Based on this, the percentage of variance for both the rainfall and OLR data is examined. OLR has a higher spatial coherence than rainfall. The first principal component of rainfall data shows high positive values, which are concentrated over northeast as well as southeast, whereas for the OLR, the area of large positive values is concentrated over northwest and lower value over south India apart from the Indian ocean. The first five principal components explain 92.20% of the total variance for the rainfall and 99.50% of the total variance for the outgoing long-wave radiation. The relationship between monsoon rainfall and Southern Oscillations has also been examined and for the Southern Oscillations, it is 0.69 for the monsoon season. The El-Niño events mostly occurred during Southern Oscillations, i.e. Walker circulation. It has been found that the average number of low pressure system/low pressure system days play an important role during active (flood) or inactive (drought) monsoon year, but low pressure system days play more important role in comparison to low pressure systems and their ratio are (16:51) and (13:25) respectively. Significantly, the analysis identifies the spatial and temporal pattern characteristics of possible physical significance. 相似文献
16.
Hourly outgoing longwave radiation(OLR) from the geostationary satellite Communication Oceanography Meteorological Satellite(COMS) has been retrieved since June 2010. The COMS OLR retrieval algorithms are based on regression analyses of radiative transfer simulations for spectral functions of COMS infrared channels. This study documents the accuracies of OLRs for future climate applications by making an intercomparison of four OLRs from one single-channel algorithm(OLR12.0using the 12.0 μm channel) and three multiple-channel algorithms(OLR10.8+12.0using the 10.8 and 12.0 μm channels; OLR6.7+10.8using the 6.7 and 10.8 μm channels; and OLR All using the 6.7, 10.8, and 12.0 μm channels). The COMS OLRs from these algorithms were validated with direct measurements of OLR from a broadband radiometer of the Clouds and Earth's Radiant Energy System(CERES) over the full COMS field of view [roughly(50°S–50°N, 70°–170°E)] during April 2011.Validation results show that the root-mean-square errors of COMS OLRs are 5–7 W m-2, which indicates good agreement with CERES OLR over the vast domain. OLR6.7+10.8and OLR All have much smaller errors(～ 6 W m-2) than OLR12.0and OLR10.8+12.0(～ 8 W m-2). Moreover, the small errors of OLR6.7+10.8and OLR All are systematic and can be readily reduced through additional mean bias correction and/or radiance calibration. These results indicate a noteworthy role of the6.7 μm water vapor absorption channel in improving the accuracy of the OLRs. The dependence of the accuracy of COMS OLRs on various surface, atmospheric, and observational conditions is also discussed. 相似文献
17.
Man‐Li C. Wu 《大气与海洋》2013,51(1):150-174
Abstract Global precipitation estimates using satellite data are derived using difference fields of outgoing long‐wave radiation (OLR). The difference fields consist of clear OLR minus cloudy OLR, which is a measure of long‐wave cloud radiative forcing at the top of the earth‐atmosphere system; and clear daytime OLR minus clear night‐time OLR, which is a measure of the diurnal variation of surface heating. All geophysical parameters used to compute OLR are derived from an analysis of the HIRS2/MSU sounding data. The derived global precipitation estimates show good agreement with collocated raingauge data over land. The correlation coefficient between the precipitation estimates derived using difference fields of OLR and raingauge data over land is about 0.65 for the FGGEyear. The correlation coefficient between precipitation estimates derived using difference fields of OLR and the GOES Precipitation Index (GPI) fraction is about 0.914 from 30°S to 30°N for July 1983, and between the precipitation estimates derived using difference fields of OLR and the difference field of atmospheric reflectance is about 0.86. Using one set of coefficients, global precipitation fields are derived for each 10‐day period and each month of the FGGE year (from December 1978 to November 1979). These fields contain rich information on seasonal variations. 相似文献
18.
The radiation budget at the top of the atmosphere plays a critical role in climate research. Compared to the broadband flux, the spectrally resolved outgoing longwave radiation or flux(OLR), with rich atmospheric information in different bands,has obvious advantages in the evaluation of GCMs. Unlike methods that need auxiliary measurements and information, here we take atmospheric infrared sounder(AIRS) observations as an example to build a self-consistent algorithm by an angular distribution model(ADM), based solely on radiance observations, to estimate clear-sky spectrally resolved fluxes over tropical oceans. As the key step for such an ADM, scene type estimations are obtained from radiance and brightness temperature in selected AIRS channels. Then, broadband OLR as well as synthetic spectral fluxes are derived by the spectral ADM and validated using both synthetic spectra and CERES(Clouds and the Earth's Radiant Energy System) observations. In most situations, the mean OLR differences between the spectral ADM products and the CERES observations are within ±2 W m~(-2), which is less than 1% of the typical mean clear-sky OLR over tropical oceans. The whole algorithm described in this study can be easily extended to other similar hyperspectral radiance measurements. 相似文献
19.
该文利用美国NOAA卫星1991年（及1980和1985年）雨季候平均OLR资料及常规天气观测资料，对1991年江淮洪涝梅雨的OLR场特征进行分析。分析了1991梅雨期的OLR及其距平场以及季内变化（ISV）的经、纬向传播特征；揭示了ITCZ与副热带高压的变化与梅雨的关系以及青藏高原OLR的异常与梅雨的关系；指出西太平洋ITCZ的提前出现以及青藏高原冬季OLR的正距平（积雪少）是1991年洪涝梅雨提前发生的先兆。最后分析了1991年梅雨活跃期与中断期的OLR分布特征，并与印度季风雨相比较，发现两者开始日期 相似文献
20.
本文利用1980～2019年美国NOAA系列卫星观测的向外长波辐射（OLR）月平均资料和欧洲中心ERA5月平均地表热通量资料,研究青藏高原（以下简称高原）地区OLR与对流活动的时空分布及其演变特征,以及地表热通量与高原夏季对流活动之间的关系。结果表明:高原地区平均OLR强度由高原周边地区向中部递减,高原东部OLR低于西部,高原东部对流活动显著强于西部;近40年高原OLR总体呈较平稳的增强趋势,存在显著的6年与2～3年的周期特征,对流活动总体呈缓慢减弱趋势,但不同区域不同季节对流活动的变化趋势存在差异,其中夏季高原对流活动呈增强趋势,其他季节则以减弱趋势为主。各季节在高原三江源地区附近对流活动均呈减弱趋势,在高原南部喜马拉雅山脉北侧地区,对流活动则呈一致的增强趋势。夏季高原地表潜热通量普遍强于地表感热通量,且二者分布型近似相反。高原对流活动演变与地表感热、潜热通量均有关,且与地表感热通量的关系更为密切,二者之间普遍存在负相关关系,且在高原西部最为显著;地表潜热通量与高原东西部对流活动间相关呈东西向偶极型分布,在高原西部二者之间存在正相关关系,在高原东部则表现为负相关。 相似文献