Spatially variable evapotranspiration over salt affected pistachio orchards analyzed with satellite remote sensing estimates
Spatially variable evapotranspiration over salt affected pistachio orchards analyzed with satellite remote sensing estimates
复制标题
利用卫星遥感估计分析受盐影响的开心果园的空间蒸发蒸散量
DOI：
10.1016/j.agrformet.2018.07.004
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发表时间：
2018
影响因子：
6.2
通讯作者：
D. Zaccaria
中科院分区：
文献类型：
--
作者：
Yufang Jin;Ruyan He;G. Marino;M. Whiting;E. Kent;B. Sanden;M. Culumber;L. Ferguson;C. Little;S. Grattan;K. Paw U;L. O. Lagos;R. Snyder;D. Zaccaria
加利福尼亚州最近的长期干旱凸显了对高价值木本作物实施更有效的水管理实践的迫切需要。准确估算蒸散量（ET）是消耗水的主要组成部分，对于改善加利福尼亚州圣华金河谷种植的微灌溉开心果果园的管理至关重要。我们利用内部校准高分辨率绘图蒸发蒸腾量 (METRIC) 方法和 Landsat 8 卫星观测，估算了 2015 年和 2016 年非盐渍土和盐渍化土壤上三个成熟商业开心果园的蒸散量。基于与8个站点现场观测的比较，我们修改了开心果树作物动量粗糙度长度和净辐射的参数化，并降低了每日ET估计的不确定性。与现场数据相比，在 Landsat 立交桥日期期间，重新校准的 METRIC ET 估计值的 R2 为 0.59，平均绝对误差为 1.1 毫米/天，RMSE 为 1.4 毫米/天（n=72）。 METRIC ET 地图捕捉了果园内部和之间的时间动态和空间异质性。遥感年平均蒸散量（2016年3月中旬至10月中旬）由无盐对照园的1064±99mm下降到土水盐分最高果园的725±82mm，下降了32%。 ET 减少与研究果园之间的树冠体积差异一致，如陆地卫星观测的夏季归一化植被指数 (NDVI) 所示，例如，对照果园为 0.72±0.06，而盐度最高的果园为 0.52±0.06。可用能量主要由冠层特征控制，并解释了所有 Landsat 像素和卫星天桥日中 64% 的每日 ET 变化。归一化水分指数（NDWI）可被视为捕获蒸散可用能量分配的重要参数（R2=0.38），表明盐渍果园较低的土壤渗透势进一步降低了作物蒸散。
Recent prolonged droughts in California have emphasized the urgent need to implement more efficient water management practices for high value tree crops. Accurate estimation of evapotranspiration (ET), a main component of consumptive water use, is critical for improving management of micro-irrigated pistachio orchards grown in the San Joaquin Valley of California. We estimated ET of three mature commercial pistachio orchards on non-saline and increasingly saline soils in 2015 and 2016, using the Mapping Evapotranspiration at high Resolution with Internalized Calibration (METRIC) method and Landsat 8 satellite observations. Based on a comparison with field observations at 8 sites, we modified the parameterizations of the momentum roughness length and net radiation for pistachio tree crops and reduced the uncertainty of daily ET estimates. When compared with field data, the recalibrated METRIC ET estimates had an R2of 0.59, a mean absolute error of 1.1 mm/day, and a RMSE of 1.4 mm/day during Landsat overpass dates (n = 72). The METRIC ET map captured the temporal dynamics and spatial heterogeneity both within and among the orchards. The mean annual crop season estimated ET (mid-March to mid-October in 2016) with remote sensing decreased by 32% from 1064 ± 99 mm in the non-salt affected control orchard to 725 ± 82 mm in the orchard with the highest level of soil-water salinity. The ET reduction was consistent with canopy volume differences among the study orchards, as shown by summer Normalized Difference Vegetation Index (NDVI) from Landsat observations, e.g., 0.72 ± 0.06 in the control vs. 0.52 ± 0.06 in the most saline orchard. The available energy was controlled mostly by canopy features and explained 64% of daily ET variation among all Landsat pixels and satellite overpass days. The normalized differenced water index (NDWI) could be considered as an important parameter to capture the partitioning of available energy for ET (R2= 0.38), suggesting that the lower soil osmotic potential in saline orchards further reduced crop ET.