Lee Sever, Pinhas Alpert, Alexei Lyapustin, Yujie Wang, Alexandra Chudnovsky A
Porter School of Environment, Tel Aviv University.
Tel Aviv University, AIRO Lab, Department of Geography and Human Environment, School of Geosciences, Israel.
Atmos Environ (1994). 2017 Sep;165:359-369. doi: 10.1016/j.atmosenv.2017.06.047. Epub 2017 Jun 29.
The extreme rate of evaporation of the Dead Sea (DS) has serious implicatios for the surrounding area, including atmospheric conditions. This study analyzes the aerosol properties over the western and eastern parts of the DS during the year 2013, using MAIAC (Multi-Angle Implementation of Atmospheric Correction) for MODIS, which retrieves aerosol optical depth (AOD) data at a resolution of 1km. The main goal of the study is to evaluate MAIAC over the study area and determine, for the first time, the prevailing aerosol spatial patterns. First, the MAIAC-derived AOD data was compared with data from three nearby AERONET sites (Nes Ziona - an urban site, and Sede Boker and Masada - two arid sites), and with the conventional Dark Target (DT) and Deep Blue (DB) retrievals for the same days and locations, on a monthly basis throughout 2013. For the urban site, the correlation coefficient (r) for DT/DB products showed better performance than MAIAC (r=0.80, 0.75, and 0.64 respectively) year-round. However, in the arid zones, MAIAC showed better correspondence to AERONET sites than the conventional retrievals (r=0.58-0.60 and 0.48-0.50 respectively). We investigated the difference in AOD levels, and its variability, between the Dead Sea coasts on a seasonal basis and calculated monthly/seasonal AOD averages for presenting AOD patterns over arid zones. Thus, we demonstrated that aerosol concentrations show a strong preference for the western coast, particularly during the summer season. This preference, is most likely a result of local anthropogenic emissions combined with the typical seasonal synoptic conditions, the Mediterranean Sea breeze, and the region complex topography. Our results also indicate that a large industrial zone showed higher AOD levels compared to an adjacent reference-site, i.e., 13% during the winter season.
死海极高的蒸发速率对周边地区有着严重影响,包括大气状况。本研究利用中分辨率成像光谱仪(MODIS)的多角度大气校正(MAIAC)算法,分析了2013年死海东西部的气溶胶特性,该算法可获取分辨率为1千米的气溶胶光学厚度(AOD)数据。本研究的主要目的是评估MAIAC算法在研究区域的表现,并首次确定主要的气溶胶空间分布模式。首先,将MAIAC算法得出的AOD数据与附近三个AERONET站点(内斯齐奥纳——一个城市站点,以及塞德博克尔和马萨达——两个干旱站点)的数据进行比较,并与同一日期和地点的传统暗目标(DT)和深蓝(DB)反演结果进行比较,时间跨度为2013年全年,按月进行。对于城市站点,DT/DB产品的相关系数(r)全年表现优于MAIAC算法(分别为r = 0.80、0.75和0.64)。然而,在干旱地区,MAIAC算法与AERONET站点的对应关系优于传统反演算法(分别为r = 0.58 - 0.60和0.48 - 0.50)。我们按季节研究了死海两岸AOD水平的差异及其变化,并计算了月度/季节AOD平均值,以呈现干旱地区的AOD模式。因此,我们证明了气溶胶浓度强烈偏向于西海岸,尤其是在夏季。这种偏向很可能是当地人为排放与典型的季节性天气状况、地中海海风以及该地区复杂地形共同作用的结果。我们的结果还表明,一个大型工业区的AOD水平高于相邻的参考站点,即在冬季高出13%。