Estimating animal densities in the aerosphere using weather radar: To Z or not to Z?
Estimating animal densities in the aerosphere using weather radar: To Z or not to Z?
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DOI：
10.1890/es12-00027.1
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发表时间：
2012-08-01
期刊：
影响因子：
2.7
通讯作者：
Kelly, Jeffrey F.
中科院分区：
文献类型：
--
作者：
Chilson, Phillip B.;Frick, Winifred F.;Kelly, Jeffrey F.
气象雷达提供近乎连续的记录和广泛的空间覆盖，这对希望在广泛的时间和空间尺度上观察和研究大气层中动物运动的生物学家来说是一种宝贵的资源。强大的生物学推论可以从雷达数据中获得，这些数据主要是为了理解气象学而处理的。然而，当寻求回答某些定量生物学问题时，e。例如，在一个实施例中，至于与动物密度有关的数据，在处理雷达数据作气象用途时所作的假设，会干扰生物推断。特别是，气象雷达报告的雷达反射系数（Z）值不太适合生物学解释。我们在这里提出的数学框架允许研究人员解释来自生物散射体（bioscatterers）的天气雷达数据，而不依赖于专门为气象现象开发的假设。讨论的数学原理被用来解释接收到的回波功率，因为它涉及到生物散射。我们使用雷达模拟器检查测量误差和这些生物散射信号之间的关系。我们的模拟结果表明，在30-90公里的雷达，距离典型的观察空中脊椎动物，如鸟类和蝙蝠，测量误差与雷达采样体积内的动物的数量密度是足够低，以允许合理的估计空中密度的人口监测。使用雷达回波量化雷达在大气层栖息地观察到的生物种群的框架，增强了雷达遥感用于长期人口监测以及其他生态应用，如物候学，运动和空中行为的研究。
Weather radars provide near-continuous recording and extensive spatial coverage, which is a valuable resource for biologists, who wish to observe and study animal movements in the aerosphere over a wide range of temporal and spatial scales. Powerful biological inferences can be garnered from radar data that have been processed primarily with the intention of understanding meteorology. However, when seeking to answer certain quantitative biological questions, e. g., those related to density of animals, assumptions made in processing radar data for meteorological purposes interfere with biological inference. In particular, values of the radar reflectivity factor (Z) reported by weather radars are not well suited for biological interpretation. The mathematical framework we present here allows researchers to interpret weather radar data originating from biological scatterers (bioscatterers) without relying on assumptions developed specifically for meteorological phenomena. The mathematical principles discussed are used to interpret received echo power as it relates to bioscatterers. We examine the relationships among measurement error and these bioscatter signals using a radar simulator. Our simulation results demonstrate that within 30-90 km from a radar, distances typical for observing aerial vertebrates such as birds and bats, measurement error associated with number densities of animals within the radar sampling volume are low enough to allow reasonable estimates of aerial densities for population monitoring. The framework presented for using radar echoes for quantifying biological populations observed by radar in their aerosphere habitats enhances use of radar remote-sensing for long-term population monitoring as well as a host of other ecological applications, such as studies on phenology, movement, and aerial behaviors.