RETRIEVING ATMOSPHERIC SOUNDING PROFILES AROUND TYPHOON YUNNA USING INFRARED HYPERSPECTRAL MEASUREMENTS AIRS

In this study,we derived atmospheric profiles of temperature,moisture,and ozone,along with surface emissivity,skin temperature,and surface pressure,from infrared-sounder radiances under clear sky (cloudless) condition.Clouds were detected objectively using the Atmospheric Infrared Sounder under a relatively low spatial resolution and cloud-mask information from the Moderate Resolution Imaging Spectroradiometer under a high horizontal resolution;this detection was conducted using space matching.Newton’s nonlinear physical iterative solution technique is applied to the radiative transfer equation (RTE) to retrieve temperature profiles,relative humidity profiles,and surface variables simultaneously.This technique is carried out by using the results of an eigenvector regression retrieval as the background profile and using corresponding iterative forms for the weighting functions of temperature and water-vapor mixing ratio.The iterative forms are obtained by applying the variational principle to the RTE.We also compared the retrievals obtained with different types of observations.The results show that the retrieved atmospheric sounding profile has great superiority over other observations by accuracy and resolution.Retrieved profiles can be used to improve the initial conditions of numerical models and used in areas where conventional observations are sparse,such as plateaus,deserts,and seas.

MODIS/NDVI和MODIS/EVI在耕地信息提取中的应用及对比分析

MODIS植被指数数据是区域土地利用信息提取的重要数据源。为了对比MODIS两种主要植被指数(NDIV、EVI)在耕地信息提取中的应用,采用通过时间序列谐波分析法(Harmonic Analysis of Time Series,HANTS),对2006年全年MODIS 16天250m的NDVI和EVI时间谱数据进行了重构,从而进行了河西走廊绿洲中东部样区一系列耕地信息的提取实验,包括耕地、休耕地识别以及耕地复种指数、作物种类提取。在此基础上,对MODIS的NDVI与EVI数据的应用进行了对比分析。结果显示:(1)利用傅立叶谐波变换得到的EVI和NDVI时间谱曲线的谐波余项及谐波振幅对耕地进行识别,从识别精度来看,EVI要优于NDVI,识别精度分别为97.17%和95.99%,Kappa系数分别达到0.7938和0.6518;(2)通过计算时间序列曲线的波峰数能够提取耕地的复种指数,并且在EVI和NDVI曲线波峰阈值分别设为0.20和0.25时,休耕地能较为准确地被识别出来;(3)通过提取作物生长期内曲线的VI最大增长速率时间点以及峰值时间点等信息,作物种类能被初步识别,并且EVI较NDVI具有更强的识别能力。

基于MODIS卫星数据的平流雾检测研究

利用MODIS卫星数据,对雾与目标物(水、云、雪、地物)分别进行采样,得到光谱曲线并进行光谱分 析,提出了有利于白天和夜间平流雾检测的波段,利用该波段选择结果,采用阈值法对平流雾进行检测并得到 地面数据验证。结果表明,MODIS数据在雾检测方面具有很大的潜力。

基于MODIS植被指数时间谱的华北平原土地覆盖分类

中分辨率成像光谱仪(M OD IS)已在全球资源环境监测中发挥了重要作用,但是它的低分辨率成为提高分类精度的阻碍。利用M OD IS的高时间分辨率弥补其低空间分辨率的不足,设计分类器改善分类精度。利用2003年23个时相的M OD IS_EV I图像,构建华北平原植被指数图像时间立方体。在谐波分析去噪标准化基础上,从EV I时间谱上提取5个表征物候差异的特征向量,结合表征地气交互作用差异的地表温度(LST)信息及表征地表固有的空间分异特征的坡度信息,建立分类二叉树进行土地覆盖分类。结果表明,与2000年TM分类结果的总体一致性为75.5%,K appa系数为0.68。而NA SA U SG S基于M OD IS分类精度为66.0051%,K appa系数为0.3209。进一步与2003年耕地面积的官方统计资料的比较表明,该文的估算误差为34.0507 khm2,而NA SA U SG S的估算误差高达66.1205 khm2。研究表明利用高时间分辨率的M OD IS植被指数时间序列获得较高精度的土地覆盖分类结果是可能的。

MODIS监测雾的方法及分析

根据云雾及下垫面在可见光、长波红外和中红外波段的反射及辐射特性差异,结合MOD IS资料,得出不同的波谱廓线并进行波谱分析。利用分析结果给出多通道综合阈值法监测大雾的流程,并用此方法进行了个例分析。结果表明:MOD IS资料在雾监测方面有很好的应用潜力;中红外通道在雾监测上有独特的优势。

基于偏差原则利用MODIS红外资料反演大气廓线以及表层温度

遥感方程或大气辐射传输方程是属于第一类非线性Fredholm积分方程,这类方程的显著特征是不适定的,尤其此类问题解的不稳定性,增加了反演的难度。因此需要研究控制反演不稳定性和提高反演精度的有效方法。为了使解稳定,光滑参数γ作为约束因子是必要的。文中结合牛顿非线性迭代法反演大气廓线,利用偏差原则来最优选择光滑参数γ,即在同步反演大气廓线的同时对γ采用分步迭代的原则。最后利用中分辨率和成像光谱仪(MODIS)红外资料进行反演试验,反演结果表明采用偏差原则选取γ明显优于经验法,反演的表层温度和大气可降水量与美国国家宇航局(NASA)的MOD07产品类似。

宝浪油田改性淀粉调剖体系配方筛选

宝浪油田储层高温高盐且含煤（隔夹）层，注入水易沿煤层窜进。为了有效封堵储层煤层，筛选了自行合成的丙烯酰胺接枝改性淀粉为主剂的凝胶配方：改性淀粉3000mg／L、乌洛托品750mg／L、间苯二酚400mg／L、草酸800mg／L；改性淀粉与鸟洛托品之比4：1时体系比较稳定。初配的体系剪切至黏度下降50％，成胶后黏度仍大于20Pa·s；该体系热老化稳定性较好，在80℃下放置90天后在80℃下测定的凝胶黏度高于20Pa·s；在60℃下放置90天后在60℃下测定的凝胶黏度高于25Pa·s。该体系对不同渗透率（0．06-0．41μm^2）岩心的封堵率在98％以上。图6表2参7。

氮气泡沫在塔河强底水砂岩油藏的应用

塔河油田砂岩油藏具有强底水、埋藏深、温度高、矿化度高等特点,强底水是其主要特征之一。为了探索此类油藏治理方案,2014年在塔河油田二区东区块和塔河九区三叠系油藏进行了氮气泡沫吞吐、调驱技术的应用。氮气泡沫技术是通过向油井中注入氮气,同时注入泡沫剂,改善调剖、驱替能力,对边底水油藏压水锥、提高采收率。现场进行了TK907H、TK923H两口井的单井吞吐试验和TK202H井组调驱试验。试验结果表明:TK907H井组驱替效果优于单井吞吐效果,TK923H井单井吞吐效果不明显,这俩井组累计产生费用273.5万元,增油4942.7t,折算吨油成本553.3元/t;TK202H井组三轮次氮气泡沫驱替累计产生费用377.1万元,增油1132.6t,吨油成本3329.5元/t,氮气泡沫体系的适应性、有效期有待进一步提高。

利用MODIS红外资料反演大气温湿度廓线的研究

概述了利用特征向量统计回归反演算法,从EOS/MODIS的红外通道资料反演大气温湿度垂直分布过程,并与美国国家环境预报中心NCEP(National Centers for Environmental Prediction)等压面再分析场资料按照纬度和气压高度进行了真实性检验。结果表明:由MODIS资料反演得到的大气温湿度参数能够揭示大气温湿度的垂直分布。在各个等压面上均方根误差平均值在中纬度地区为3.39 K,低纬度地区为1.40 K,近地面层、对流层顶附近及下垫面地形复杂的区域误差较大,总体上低纬度地区要好于中纬度地区。反演的水汽误差也为低纬度地区小于中纬度地区,且随高度升高,中、高纬度误差均逐渐减小并接近。

20 TO 30-DAY AND 30 TO 60-DAY OSCILLATIONS IN ASSIMILATED GLOBAL DATASETS USING TRMM RAINFALL OBSERVATIONS

The influences of Tropical Rainfall Measuring Mission （TRMM） precipitation products on the structure and underlying physics of intraseasonal oscillation （ISO） are investigated with the U.S. National Aeronautics and Space Administration Goddard Earth Observing System model version 3 （GEOS-3） data assimilation system （DAS）. The strong ISO phase in the 1998 summer is apparently located in the Asian monsoon region and the east equatorial Pacific region. The eastward propagation is a dominant feature for the tropical ISO at 20 to 30-day oscillation while the northeastward propagation is the salient ISO at 30 to 60-day oscillation over the 10~N to 25~N belt region. It appears that the Kelvin wave structure is for the tropical 20 to 30-day oscillation. The tropical 30 to 60-day oscillation has the characteristics of the Kelvin-Rossby wave. The impact of satellite-derived precipitation （and its associated latent heating） on the ISO intensity is limited in the GEOS-3 assimilation system. However, its impact on the ISO spatial structures is obvious. Overall, the results demonstrate a better eastward propagation and a northward propagation of ISO with the TRMM precipitation simulation, indicating that latent heating is very important in exciting the equatorial ISO. Key words： 20 to 30-day oscillation; 30 to 60-day oscillation; GEOS data assimilation system; Kelvin wave; TRMM precipitation

Evaluation of Terra/MODIS atmospheric profiles product(MOD07)over the Iberian Peninsula:a comparison with radiosonde stations

Remote sensing techniques are a useful tool for continuous observation of the Earth at global scale.However,products derived from remote sensing data require a rigorous validation using in situ data.Moderate Resolution Imaging Spectroradiometer(MODIS)is not really a sounding instrument,but it does have 16 infrared bands(bands 20-36 covering the spectral range from 3μm to 14μm)that allow the retrieval of temperature and moisture profiles as well as total column integrated magnitudes.In this paper we show the results obtained in the evaluation of MOD07 daytime and nighttime products over the Iberian Peninsula during the decade from 2000 to 2010 using nine radiosonde stations.Although MODIS limitations in comparison with other sounding instruments,the validation provided satisfactory results,with bias(MOD07 minus radiosonde)<0.3 cm and a standard deviation of 0.5 cm for the total column water vapor,and bias around 1 K on average with standard deviations between 2 K and 3 K for air temperature at different pressure levels.On average,bias was positive and below 2 K with standard deviations around 5 K for the dew point temperature case.Large errors were found in this case for pressure levels higher than 50 hPa.

Physics-based simultaneous retrieval of atmospheric temperature-humidity profiles and land surface temperature-emissivity by integrating Terra/Aqua MODIS measurements

Atmospheric temperature-humidity profiles and land or sea surface temperature are coupled actions in the earth system process. Based on the numerical perturbation form of the atmospheric radiative transfer equation, a physics-based algorithm is pre- sented to integrate four pairs of MODIS measurements from the Terra and Aqua satellites to retrieve simultaneously atmospheric temperature-humidity profile, land-surface temperature and emissivity. Three pairs of MODIS data at two field sites in China, Luancheng and Poyang Lake areas, have been chosen to test and validate the model. Two pairs of atmospheric tem- perature and humidity profiles, land surface temperature (LST), and land surface emissivity (LSE) have been retrieved simul- taneously for every pair of MODIS measurements respectively by the proposed physical algorithm for the study area. The synchronous field measurements at two field sites were conducted to validate the retrieval LST, the differences between the retrieved LST and the field measurements are in the range of -0.15 K and 1.11 K. The emissivity errors of MODIS bands 31 and 32, compared with the EOS MODIS LST/LSE data products (MOD11_L2/MYD11_L2 V5) by the physics-based day/night algorithm, are from 0.0018 to 0.44 and from 0.0058 to 1.24, respectively. Meanwhile, the retrieved atmospheric profiles fully agree with the standard atmospheric temperature-water vapor profiles and with the results from single MODIS data onboard Terra or Aqua satellite by the former two-step physical algorithm. Therefore, the proposed algorithm is robust enough to improve the retrieval accuracy of the atmospheric profiles and land surface parameters. And it will have four pairs of the retrieval results for one area each day by integrating these MODIS measurements from Terra and Aqua satellites.

Modification and validation of a new method to improve the accuracy of MODIS-derived dew point temperature over China's Mainland

MODIS atmospheric profile products(MOD07_L2 and MYD07_L2)have been widely used for near-surface dew point temperature(T_(d))estimation.However,their accuracy over large scale has seldom been evaluated.In this study,we validated these two products comprehensively against 2153 stations over China's Mainland.MOD07_L2 was suggested by our study because it achieved higher accuracy in either of two frequently-used methods.To be specific,the root-meansquare error(RMSE)achieved by MOD07_L2 and MYD07_L2 was 5.82 and 7.42℃,respectively.On this basis,a recent ground-based correction method was modified to further improve their accuracy.Our focus is to investigate whether this ground-based approach is applicable to large-scale remote sensing applications.The results show that this new method showed great potential for T_(d) estimation independently from ground observations.Through the introduction of MODIS land surface products,the RMSE it achieved for MOD07_L2 and MYD07_L2 was 5.23 and 5.59℃,respectively.Further analysis shows that it was particularly useful in capturing the annual average T_(d) patterns.The R2,RMSE,and bias of annual average daily mean T_(d) estimates were 0.95,1.84℃,and 0.53℃,and those achieved for annual average instantaneous T_(d) estimates were 0.94,2.09℃,and 0.75℃,respectively.

利用MODIS红外资料反演大气参数以及表层温度的研究

提出了用牛顿非线性迭代法同时反演大气参数和表层温度,该反演算法应用到我国渤海地区MODIS红外资料中,可反演得到中尺度范围内的大气温度、水汽廓线,其误差分别不超过1.5 K和18%。反演得到的表层温度、大气可降水量(TPW)和大气稳定度(TTI)与美国国家宇航局(NASA)MOD07产品相似。

Underestimation of Oceanic Warm Cloud Occurrences by the Cloud Profiling Radar Aboard Cloud Sat

The Cloud Profiling Radar （CPR） onboard CloudSat is an active sensor specifically dedicated to cloud detection. Compared to passive remote sensors, CPR plays a unique role in investigating the occurrence of multi-layer clouds and depicting the internal vertical structure of clouds. However, owing to contamination from ground clutter, CPR reflectivity signals are invalid in the lowest 1 km above the surface, leading to numerous missed detections of warm clouds. In this study, by using 1-yr CPR and MODIS （Moderate Resolution Imaging Spectroradiometer） synchronous data, those CPR-missed oceanic warm clouds that are identified as cloudy by MODIS are examined. It is demonstrated that CPR severely underestimates the occurrence of oceanic warm clouds, with a global-average miss rate of about 0.43. Over the tropical and subtropical oceans, the CPR-missed clouds tend to occur in regions with relatively low sea surface temperature. CPR misses almost all warm clouds with cloud tops lower than 1 km, and the miss rate reduces with increasing cloud top. As for clouds with cloud tops higher than 2 kin, the negative bias of CPR-captured warm cloud occurrence falls below 3%. The cloud top height of CPR-missed warm clouds ranges from 0.6 to 1.2 kin, and these clouds mostly have evidently small optical depths and droplet effective radii. The vertically integrated cloud liquid water content of CPR-missed warm clouds is smaller than 50 g m 2 It is also revealed that CPR misses some warm clouds that have small optical depths or small droplet sizes, besides those limited in the boundary layer below about 1 km due to ground clutter.