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首页> 外文期刊>Journal of Geophysical Research. Biogeosciences >An accumulation map for the Greenland dry-snow facies derived from spaceborne radar - art. no. 4280
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An accumulation map for the Greenland dry-snow facies derived from spaceborne radar - art. no. 4280

机译：从星载雷达获得的格陵兰干雪相的累积图-艺术没有。 4280

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1] An important component of ice sheet mass balance calculations is the snow accumulation rate, traditionally determined across the ice sheet from interpolated ice core data. We derive an accumulation rate map within the Greenland dry-snow facies, using C-band radar backscatter and the mean annual temperature. Values for the backscatter were obtained from the ERS-1 synthetic aperture radar mosaic acquired during September November 1992. An empirical equation, based on elevation and latitude, is used to determine the mean annual temperature. We examine the influence of accumulation rate, and mean annual temperature on C-band (5.3 GHz) radar backscatter, using a forward model, which incorporates snow metamorphosis and radar backscatter components. Our model is run over a range of accumulation and temperature conditions, consistent with the Greenland dry-snow facies. On the basis of our modeled results, a look-up table is generated, which uniquely maps the measured radar backscatter and mean annual temperature to accumulation rate. Our results compare favorably (15.4% average difference) with 124 in situ accumulation rate measurements falling within our study area. We attribute some of the differences to ( 1) unreliable in situ data points, which were based on a single year's accumulation and ( 2) a systematic underestimate of accumulation rate by our forward model in the low-accumulation regions associated with the northern portion of our map. With questionable data points and those above 77 degreesN removed, the average differences were less than 10.3%, as determined from 73 ice cores. [References: 53
机译：1]冰盖质量平衡计算的一个重要组成部分是积雪率，积雪率通常是根据内插冰芯数据在整个冰盖上确定的。利用C波段雷达的反向散射和年平均温度，我们得出了格陵兰干雪相内的累积速率图。反向散射值是从1992年9月获得的ERS-1合成孔径雷达镶嵌图获得的。使用基于海拔和纬度的经验方程式来确定年平均温度。我们使用正向模型研究了积雪率和年平均温度对C波段（5.3 GHz）雷达反向散射的影响，该模型结合了雪变质和雷达反向散射成分。我们的模型在一定范围的累积和温度条件下运行，与格陵兰的干雪相相符。根据我们的建模结果，将生成一个查询表，该表将测得的雷达反向散射和年平均温度与累积速率唯一地对应起来。我们的结果与研究范围内的124个原位累积速率测量值相比具有可观的优势（平均差异为15.4％）。我们将某些差异归因于（1）不可靠的原地数据点，这些数据点是基于一年的累积量，以及（2）我们的前向模型在与北部北部相关的低累积量区域中系统地低估了累积率。我们的地图。根据73个冰芯确定的可疑数据点和高于77°N的那些数据点，平均差异小于10.3％。 [参考：53

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