Climate-scale analysis of changing air and water masses (CLAW)

这个项目致力于测量全球降雨量的变化，并确保气候的计算机模型可以预测未来降雨量将如何变化。随着二氧化碳和其他温室气体不断添加到大气中，据了解，地球表面的温度将会上升。更温暖的空气可以容纳更多的水分，因此随着地球变暖，大气从地球表面提取水分并将其倾倒回地球的速度也将增加。对许多人来说，准确了解未来全球降雨率将发生多少变化非常重要，其中包括想知道种植哪些作物的农民，以及想要建设国内水利和水电基础设施的国家。测量世界各地的总降雨量绝非易事。在陆地上，测量是直接的(通过捕捉雨水)或通过可靠的基于河流流量和土壤湿度的间接方法进行的。然而，全球三分之二的土地被海洋覆盖。在海洋中央，如果不亲自去抓雨，是很难做到的。尽管存在许多测量海洋降雨量的“间接”方法，但在过去50年左右的时间里，海洋上的降雨量到底发生了多少变化，仍然存在很大的不确定性。谢天谢地，有一个解决方案。海洋本身就像一个巨大的雨水捕集器。以雨的形式降落的水是淡水，就像我们喝的水一样。然而，海洋的大部分都是非常咸的。因此，降雨量越大，海水就越新鲜，蒸发越多，海水就越咸。海洋学家可以测量海洋中的水的含盐量，而且50多年来一直在定期测量。然而，问题仍然存在，如何将对海洋盐度的测量转化为对降雨量的测量？嗯，通过环顾全球，计算出还有多少咸水和多少淡水，研究人员可以估计有多少水在一个地方蒸发，在另一个地方以降雨的形式下降。参与这个项目的研究人员将利用过去50年来对海洋盐度的所有观测结果来完成这项工作。他们将估计到底有多少降雨发生了变化。他们将把这一点与通常用于预测未来会发生什么的计算机模型进行比较，看看它们有多准确，以及如何改进。

This project is concerned with measuring changes in global rainfall and ensuring that computer models of the climate can predict how rainfall will change in the future.As carbon dioxide and other greenhouse gases are continually added to the atmosphere, it is understood that the temperature of the surface of the earth will rise. Warmer air can hold more moisture, so as the Earth warms the rate at which the atmosphere extracts water from the surface of the earth and dumps it back as rain will also increase. Knowing precisely how much global rates of rainfall will change into the future is important to many people including farmers wanting to know which crops to plant and nations wanting to build domestic water and hydroelectric infrastructure. Measuring the total rainfall around the world is no mean feat. On land, measurements are made directly (by catching the rain) or by reliable 'indirect' methods based on river flow and how wet the soil is. However, two-thirds of the globe is covered by ocean. It is hard to catch rain in the middle of the ocean without actually being there to do it. Although many 'indirect' methods exist for measuring rainfall over the ocean there is great uncertainty about how much rainfall has changed over the ocean in the last 50 years or so. Thankfully there is a solution. The ocean itself acts as a giant rain catcher. Water that falls as rain is fresh water, like the water we drink. Most of the ocean however, is very salty. So the more rain that falls, the fresher the ocean water gets and the more evaporation that occurs the saltier the ocean water gets. Oceanographers can measure just how salty the water in the ocean is and have been doing so regularly for more than 50 years now. The question remains however, how do you turn measurements of the salinity of the ocean into measurement of how much rain has fallen? Well, by looking all around the globe and counting up how much more salty water there is and how much fresh water there is, researchers can estimate how much water has been evaporated in one place and fallen as rain in another. The researchers involved in this project will do this using all the observations of salinity in the ocean taken over the last 50 years. They will estimate just how much rainfall has changed. They will compare this with computer models which are commonly used to predict what will happen in the future to see how accurate they are and how they can be improved.