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

该项目支持新汉普郡大学、科罗拉多大学/科罗拉多大学和尼泊尔水文和气象局(DHM)合作开展的一项气溶胶采样计划。气溶胶中可溶离子物种、有机碳和元素碳的浓度将在这些监测站连续测定大约两年的时间(按名义上的两天分辨率)。每个站点的连续多波长气溶胶光学厚度测量将补充这一滤光片采样。一个空间站将设在加德满都附近，另一个设在海拔4100米的地方。主要目标是确定气团从南向北穿越尼泊尔并与喜马拉雅地块相遇时气溶胶含量的变化。来自孟加拉湾的夏季季风空气和冬季西风的交替影响预计将在气溶胶的浓度和组成方面造成很大的季节变化。光学厚度测量将提供关于地表气团和上覆柱中气溶胶负荷之间关系的信息。目前对中亚大部分地区的大气化学知之甚少，因为在这个广阔的区域缺乏系统的采样。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以极大地改变区域气候，包括夏季风的强度，从而改变急需的降雨量。

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.