Collaborative Research: Measurement of Aerosol Chemical and Radiative Properties in Nepal

该项目支持一项气溶胶取样计划，该计划将在新罕布什尔州大学、科罗拉多大学/CIRES和尼泊尔水文和气象部（DHM）之间合作开展。将在这些台站连续测定气溶胶中可溶性离子种类、有机碳和元素碳的浓度（标称分辨率为2天），为期约两年。这种过滤器取样将辅之以在每个台站连续进行多波长气溶胶光学厚度测量。一个站将位于加德满都附近，另一个站位于海拔4100米处。主要目的是确定气溶胶含量的变化，因为他们穿越尼泊尔从南到北，遇到喜马拉雅山地块。来自孟加拉湾的夏季季风空气和冬季西风带的交替影响预计将导致气溶胶浓度和成分的季节性变化。光学深度测量将提供关于表面空气质量与上覆气柱中悬浮微粒含量之间关系的信息。由于在这一广阔区域缺乏系统的采样，目前对中亚大部分地区的大气化学知之甚少。中亚季风环流是亚洲人口稠密地区的主要水源，也是全球气候系统的主要组成部分。模型预测表明，人为改变大气成分可能会极大地改变区域气候，包括夏季季风的强度，从而改变急需的降水量。

This project supports an aerosol sampling program that will be carried out in collaboration between the University of New Hampshire, the University of Colorado/CIRES, and the Nepalese Department of Hydrology and Meteorology (DHM). The concentrations of soluble ionic species, organic carbon and elemental carbon in aerosol will be determined on a continuous basis (at a nominal 2-day resolution) at these stations for approximately two years. This filter sampling will be complemented by continuous multi-wavelength aerosol optical depth measurements at each station. One station will be situated near Kathmandu, and the other at an altitude of 4100 m. The primary objective is to determine the modifications in the aerosol content of air masses as they traverse Nepal from south to north and encounter the Himalayan Massif. The alternating influence of summer monsoon air from the Bay of Bengal and wintertime westerlies are expected to cause large seasonal variations in the concentration and composition of aerosols. Optical depth measurements will provide information on the relationships between surface-level air masses and the aerosol burden in the overlying column. Little is currently known about the atmospheric chemistry over much of central Asia due to a lack of systematic sampling in this broad region. The central Asian monsoon circulation is the primary source of water for densely populated regions of Asia, and is also a major component of the global climate system. Model predictions suggest that anthropogenic modifications of atmospheric composition could greatly modify regional climate, including the strength of the summer monsoon and therefore the amount of much needed precipitation.