Hawaii Cyclonic Eddies and Blue Marlin Catches: The Case Study of the 1995 Hawaiian International Billfish Tournament

The combination of prevailing northeasterly tradewinds and island topography results in the formation of vigorous, westward propagating cyclonic eddies in the lee of the Hawaiian Islands on time scales of 50–70 days. These mesoscale (∼10² km) features are nowhere more conspicuous or spin up more frequently than in the Alenuihaha Channel between the Island of Maui and the Big Island of Hawaii. Cyclonic eddies in subtropical waters such as those around Hawaii vertically displace the underlying nutricline into the overlying, nutrient-depleted euphotic zone creating localized biologically enhanced patches. Insight into how these eddies may directly influence pelagic fish distribution is provided by examination of recreational fish catch data coinciding with the presence of eddies on the fishing grounds. We highlight the 1995 Hawaii International Billfish Tournament in which a cyclonic eddy dominated the ocean conditions during the weeklong event and the fish catch distribution differed significantly from the average historical tournament catch patterns. On the tournament fishing grounds, well-mixed surface layers and strong current flows induced by the eddy's presence characterized the inshore waters where the highest catches of the prized Pacific blue marlin (Makaira mazara) occurred, suggesting possible direct (e.g., physiological limitations) or indirect (e.g., prey availability) biological responses of blue marlin to the prevailing environment. This revised version was published online in August 2006 with corrections to the Cover Date.     

渤海、黄海、东海AVHRR海表温度场的季节变化特征

海表温度场表征了海洋热力、动力过程和海洋与大气相互作用的综合结果.它不仅是研究海面水汽和热量交换的一个重要物理参数,也为海洋环流、水团、海洋锋、上升流和海水混合等海洋学课题的研究提供一种直观的指示量.20世纪60年代以来,我国海洋工作者在历次海上观测和台站资料的基础上,对渤海、黄海、东海表层温度的空间分布和变化进行了较为详细的分析研究[1～4],并绘制了系列的水温气候图集.这些研究成果对认识黄海、东海海域的平均海表温度场的分布、变化以及相关物理海洋现象的研究起到了重要的作用.     

Mapping land degradation by comparison of vegetation production to spatially derived estimates of potential production

There is an urgent need for quantitative methods by which actual, as opposed to potential degradation can be mapped using spatially consistent criteria for large regions. This study tested the Local NPP Scaling (LNS) method, where the growth season sum NDVI (∑NDVI), a surrogate for productivity, of each pixel was expressed relative to the highest values (90th percentile) of ∑NDVI observed in all pixels falling within the same land capability unit (LCU). The objective of this study was to determine if the LNS approach can be used to map degraded areas: (i) by determining if areas with low LNS values co-occur with degraded areas mapped with Landsat TM and (ii) testing the persistence of these areas over multiple years. Most of the areas with low LNS values did coincide with degraded areas, with the exception of four LCUs, which either contained steep precipitation gradients or landscape variability, which probably obscured the human impacts. The performance of the LNS method is therefore largely determined by the level of detail of the stratification data (e.g. LCUs) used. The conclusion is that the LNS method is a valuable tool for mapping land degradation at a regional scale.     

NOAA/AVHRR卫星海表温度在西北太平洋的印证及分析

本文详细分析了TeraScan系统反演NOAA/AVHRR卫星海表温度的过程,解决了反演过程中的海陆匹配问题和云检测过程中的误检、漏检问题,处理得到2002年(5°～45°N)、(105°～150°E)区域内的卫星海表温度数据.利用东北亚地区海洋观测系统NEAR-GOOS提供的现场海表温度数据做比较,印证NOAA/AVHRR海表温度在西北太平洋海域的精度,并分析其误差产生的来源.     

利用NOAA/AVHRR资料监测云南大面积干旱的业务流程

介绍了利用NOAA／AVHRR资料进行云南大面积干旱监测的方法和业务流程，讨论了干旱指标、面积估算方法、作物干旱识别、产品制作等关键问题，并对1999年春季的曲靖市监测结果作了详细分析。结果表明，在云南利用卫星遥感技术对大范围干旱的面积、程度、空间分布等动态变化监测是可行的。     

NOAA/AVHRR 资料在青海省牧区草场旱情监测中的应用

文章介绍了遥感监测草场旱情的原理,提出了利用距平植被指数和干旱指数确定干旱区和干旱等级的方法。应用此方法评估1995年青海省牧区草场旱情,与农业气象旬报的旱情分析吻合较好。     

黑河实验区AVHRR反射率资料的各向异性订正

本文利用1988年9月黑河实验预试验期晴天AVHRR资料分析了实验区反射率观测值和植被指数对卫星观测角的依赖关系,讨论了应用Taylor和Stowe的各向异性订正函数对反射率观测值进行订正的效果及存在的问题。分析结果表明:Taylor和Stowe的订正函数的应用有较好的订正效果,但对高反射率的戈壁沙漠和低反射率的山地森林地区仍存在一定偏差。植被指数基本上不依赖于卫星观测角,但观测区处在星下点附近时测得的植被指数值要比远离星下点时大一些。     

大气沙尘辐射特性的卫星观测

对１９９１年３－５月在ＨＥＩＦＥ实验区过境的１０次ＡＶＨＲＲ测量资料和同期大气浑浊度观测资料的分析结果表明,ＡＶＨＲＲ资料可用于大气沙尘对地系统辐射能收支影响的研究。     

利用NOAA/AVHRR数据获取地表特征参数的方法研究

地表特征参数的正确与否直接影响到区域陆面蒸散量估算精度,因此在区域非均匀陆面蒸散研究中,地表特征参数的获取方法是一个值得探讨的问题．与传统的方法相比,卫星遥感技术在求取地表特征参数时有其独特的优势．NOAA气象卫星AVHRR资料以其时间分辨率高、覆盖面广、价格低廉等优点广泛应用于非均匀陆面蒸散研究和应用中．本文建立了NOAA／AVHRR计算地表特征参数的参数化模型,选取中国东北松嫩平原西部地区2000年7月8日的AVHRR资料,试算了研究区地表温度、地表发射率、地表反照率、NDVI等主要地表特征参数,并且参照2000年研究区土地利用数据对各参数的空间分布特征及合理性进行了分析。     

Application of nonlinear multi-channel algorithms for estimating sea surface temperature with NOAA-14 AVHRR data

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