Impact of African Dust on Clouds and Precipitation in a Caribbean Tropical Montane Cloud Forest

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。该项目将结合实地调查和建模调查，以解决远程运输非洲尘埃（LRTAD）气溶胶的物理化学特性如何影响加勒比海云特性和波多黎各独特的热带山地云雾林（TMCF）的降水水平。TMCFs在全球范围内出现在美洲、非洲和亚洲，是饮用水的主要来源。将测试三个主要假设：1)在强LRTAD期间，TMCF的云性质是否不同；2) LRTAD是否具有影响云性质和过程的独特化学和物理性质；3)降水模式与LRTAD事件的相关性如何？这项研究将在波多黎各（PR）的皮科德尔埃斯特（PE）和圣胡安角（CSJ）站进行。PE位于海拔1051米的TMCF内，处于/高于云凝结高度。这个位置有利于云的研究，而不需要飞机研究，这降低了整体的复杂性和成本，同时允许在单个云内进行更长期的观测。CSJ是全球大气监视的近海平面区域站，位于PE的逆风位置，是PR信风气团的第一个接触点。该站点允许对进入云中（云下气溶胶）的气溶胶特性进行采样。关于气溶胶、云和雨水样本的化学和物理性质的数据将通过长期测量和在第二年的密集实地活动中收集。将利用这些结果结合现有的降水、云量、温度和湿度剖面以及地表能量收支数据集，调查降水分布对LRTAD事件的敏感性，特别侧重于加勒比夏季旱季的长度和强度。未被充分代表的学生群体将与科学家和最先进的仪器进行互动，并获得独特的研究机会。区域应对AD和气候变化的能力将得到加强。项目成果将用于各种教育水平的学生和社区的教材中。“大气科学短期强化课程方案”将在波多黎各-里奥彼德拉斯大学（UPR-RP）提供短期课程，并在参与机构之间交换学生，这将弥补UPR-RP不存在的大气科学课程。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The project will combine field and modeling investigations to address how the physico-chemical properties of long range transported African dust (LRTAD) aerosol influence Caribbean cloud properties and precipitation levels in a unique Puerto Rican tropical mountain cloud forest (TMCF). TMCFs occur globally in the Americas, Africa, and Asia and represent a primary source of drinking water. Three major hypotheses will be tested: 1) are cloud properties in the TMCF different during intense LRTAD periods; 2) Does LRTAD have unique chemical and physical properties which influence cloud properties and processes; 3) what is the correlation between precipitation patterns and LRTAD events? The study will be performed in Puerto Rico (PR), at Pico del Este (PE) and Cape San Juan (CSJ) stations. PE is in a TMCF with an elevation of 1051m asl which is at/above the cloud condensation level. This location facilitates the study of clouds without the need for aircraft studies which reduces the overall complexity and costs while allowing longer term observations within a single cloud. CSJ is a near sea level regional station of the Global Atmosphere Watch, upwind from PE, and is the first contact point for the trade wind air masses in PR. This station allows the sampling of the properties of the aerosol that enter the cloud (below-cloud aerosol). Data on the chemical and physical properties of aerosols, clouds, and rainwater samples will be collected via long term measurements and during an intensive field campaign in year 2. Using these results in conjunction with existing data sets of precipitation, cloud cover, temperature and humidity profiles and surface energy budgets, the sensitivity of precipitation distribution to LRTAD events will be investigated, particularly focusing on the length and intensity of the summer dry season in the Caribbean. Underrepresented student groups will interact with scientists and state-of-the-art instrumentation and be exposed to unique research opportunities. The regional capacity to cope with AD and climate change will be strengthened. Project results will be used in educational materials for students and communities over a range of educational levels. The "Program of Intensive Short Courses in Atmospheric Sciences", where CoPIs/collaborators will offer a short course at the University of Puerto Rico-Rio Piedras (UPR-RP), as well as the exchange of students among participating institutions will compensate for the non-existent curricula in atmospheric sciences at the UPR-RP.