Projected Responses of Extreme Precipitation and Atmospheric Radiative Energy (PREPARE)

极端降水和大气辐射能的预计响应（PREPARE）

• 批准号: NE/G015708/1
• 负责人: Richard Allan
• 金额: $ 32.41万
• 依托单位: University of Reading
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FG015708%2F1
• 关键词: Projected; Responses; Extreme; Precipitation; Atmospheric

Projected increases in rainfall and its intensity and the coverage of regions experiencing drought will lead to adverse impacts on societies, agriculture and health. An emerging body of evidence indicates that climate models may underestimate the current changes in the global water cycle. It is crucial and timely that the causes of discrepancies between simulated and observed responses of the atmospheric hydrological cycle to warming are identified and addressed. Bringing together important lines of research and collaborators with unique expertise the current proposal seeks to test the following hypotheses: (i) Are limitations of the satellite data hampering our ability to monitor changes in the global water cycle? (ii) Are present day changes in the Earth's energy balance relating to aerosol influencing trends in the hydrological cycle? (iii) What are the implications for projections of future changes in rainfall and its extremes? To answer these questions, an appreciation for the root causes of changes in rainfall is required. Evidence from sophisticated climate models and observations from a variety of sources point to robust increases in atmospheric moisture with warming at about the rate expected from basic physical considerations (around 7% per K warming). Rising moisture fuels intensification of the heaviest rainfall events. This is not the full story: global precipitation is intrinsically linked to Earth's atmospheric energy budget. The relatively slow rises in atmospheric radiative cooling, as the planet warms, can only support modest rises in latent heating through precipitation of around 1-3% per K, much slower than the rises in heavy rainfall. This leads to a reduction in rainfall away from convective regimes. While both climate models and satellite observations indicate that the dry regions are becoming drier and the wet regions wetter, further comparison suggests that the models underestimate this response. To understand the reasons for the important discrepancy between models and data, we bring together important areas of expertise in the Earth's energy balance and the Global water cycle. The three main approaches are to (i) monitor, (ii) inter-compare and (iii) understand and predict changes in the hydrological cycle. These can be achieved by employing a unique combination of satellite and surface-based measurements of precipitation, evaporation and the Earth's radiative energy balance. Inter-comparison of existing and new satellite datasets will allow improved monitoring of changes in key variables such as precipitation and evaporation. Combining the hydrological and radiative components of the energy and water balance in models and observational data will enable a better understanding of the physical processes involved and improve estimates of changes in the surface radiation budget. Carefully constructed model experiments will explore the impact of changes in aerosol on the hydrological cycle through radiative forcings. The results will be paramount in improving estimates of future impacts from changes in the hydrological cycle on societies and ecosystems.

预计降雨量及其强度的增加以及干旱地区的覆盖范围将对社会、农业和健康产生不利影响。新出现的大量证据表明，气候模型可能低估了全球水循环目前的变化。查明和解决大气水文循环对变暖的模拟和观测反应之间的差异的原因是至关重要和及时的。目前的建议汇集了重要的研究领域和具有独特专门知识的合作者，试图检验以下假设：卫星数据的局限性是否妨碍了我们监测全球水循环变化的能力？(ii)当今地球能量平衡的变化是否与气溶胶影响水文循环趋势有关？(iii)对未来降雨量及其极端变化的预测有何影响？要回答这些问题，需要了解降雨量变化的根本原因。来自复杂的气候模型和各种来源的观测的证据表明，随着基本物理考虑所预期的升温速度（每K升温约7%），大气湿度将大幅增加。上升的湿度加剧了最严重的降雨事件。这并不是全部的故事：全球降水量与地球的大气能量预算有着内在的联系。随着地球变暖，大气辐射冷却相对缓慢的上升，只能通过每K约1-3%的降水来支持潜热的适度上升，比强降雨的上升要慢得多。这导致降水量减少远离对流制度。虽然气候模型和卫星观测都表明，干旱地区正在变得更干燥，潮湿地区正在变得更潮湿，但进一步的比较表明，模型低估了这种反应。为了了解模型和数据之间存在重大差异的原因，我们汇集了地球能量平衡和全球水循环的重要专业领域。三种主要方法是：（一）监测，（二）相互比较，（三）了解和预测水文循环的变化。通过采用独特的卫星和地面测量相结合的办法，可以实现这些目标，这些办法包括对降水、蒸发和地球辐射能量平衡的测量。对现有和新的卫星数据集进行相互比较将有助于改进对降水和蒸发等关键变量变化的监测。在模型和观测数据中结合能量和水平衡的水文和辐射组成部分，将有助于更好地了解所涉及的物理过程，并改进对地表辐射收支变化的估计。精心构建的模型实验将探索气溶胶的变化通过辐射强迫对水文循环的影响。研究结果对于更好地估计水文循环变化对社会和生态系统的未来影响至关重要。

项目成果

Climate Warming-Related Strengthening of the Tropical Hydrological Cycle

与气候变暖相关的热带水文循环的加强

• DOI: 10.1175/jcli-d-12-00222.1
• 发表时间: 2013
• 期刊: Journal of Climate
• 影响因子: 4.9
• 作者: Allan R

Regime dependent changes in global precipitation

• DOI: 10.1007/s00382-011-1134-x
• 发表时间: 2012-08
• 期刊: Climate Dynamics
• 影响因子: 4.6
• 作者: R. Allan

Diagnosing links between atmospheric moisture and extreme daily precipitation over the UK

诊断英国大气湿度和极端每日降水之间的联系

• DOI: 10.1002/joc.4547
• 发表时间: 2015
• 期刊: International Journal of Climatology
• 作者: Allan R

Examination of long-wave radiative bias in general circulation models over North Africa during May-July

5-7月北非大气环流模型中长波辐射偏差的检验

• DOI: 10.1002/qj.717
• 发表时间: 2010
• 期刊: Quarterly Journal of the Royal Meteorological Society
• 影响因子: 8.9
• 作者: Allan R