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Transitions Between Suppressed and Active Convection Coupled to Large-Scale Tropical Circulations

与大规模热带环流耦合的抑制对流和活跃对流之间的转变

基本信息

批准号：
NE/K004034/1
负责人：
Steven Woolnough
金额：
$ 48.19万
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：
2013
资助国家：
英国
起止时间：
2013 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FK004034%2F1
关键词：
Transitions Between Suppressed Active Convection

项目摘要

The weather and climate of the tropics is dominated by convection. Convection communicates to the rest of the atmosphere the heating and evaporation at the earth's surface. Understanding the location, timing and strength of tropical convection is crucial for understanding the global climate system. Accurate and reliable simulations by both weather-forecast and climate-prediction models require a faithful representation of convective processes and their interactions with features in the large-scale flow. The meteorology of the tropics is profoundly affected by large-scale coherent motions across thousands of kilometres. However, the energy source driving such motions is the latent heating associated with convective motions on scales of hundreds of metres. Thus, the two-way interactions between convection and large-scale flow are key to tropical meteorology. The relevant processes operate across a wide range of time and space scales and perhaps partly for that reason they are not well-captured by the numerical models used for weather and climate studies. The numerical models are incapable of representing explicitly the atmospheric processes on all space and time scales. Rather motions with short scales must be taken into account by using parameterization schemes. A model will contain a number of such schemes, each attempting to represent the effects on the model scales of a particular small-scale process that has been omitted. These processes will include turbulence in the atmospheric boundary layer, gravity waves and convection.A powerful tool for studying convection is the Cloud Resolving Model (CRM). Such models can be used to perform high-resolution simulations in which the convection is not parameterized but is explicitly modelled. Parameterization schemes are often developed and tested through comparisons with the results of CRM simulations. However, the CRM simulations are typically set up by prescribing a large-scale circulation. Thus, they are generally used to examine the response of the convection to a pre-defined situation. Such simulations make a sharp distinction between the convection and the large-scale. In reality, there is no such sharp distinction; indeed, there are strong two-way interactions between convection and the large-scale circulation. As a result, the CRM simulations are over-constrained: limited in their possible responses and unsuited for studying the interaction mechanisms.In recent years, a number of techniques have been developed for approximating the response of the large-scale tropical circulation to the heating associated with convection. These approximations provide a basis for modelling the interactions between convection and the large-scale circulation within a CRM. This means that the large-scale no longer has to be prescribed in the simulation but instead it will evolve in response to the explicitly simulated convection. Studies using these approximations have produced some valuable and intriguing results. In this project we will assess the relative merits of some of these approaches for different problems in tropical convection and exploit them to investigate the role of interactions between convection and the large-scale circulation in tropical variability.We will also apply this same framework to assess the behaviour of existing convection parameterization schemes, providing the atmospheric modelling community with a new paradigm for carefully-controlled and rigorous testing of weather-and-climate models.

热带地区的天气和气候以对流为主。对流把地球表面的加热和蒸发作用传递给大气的其余部分。了解热带对流的位置、时间和强度对于了解全球气候系统至关重要。天气预报和气候预测模式的准确和可靠的模拟需要忠实地表示对流过程及其与大尺度流特征的相互作用。热带地区的气象学深受跨越数千公里的大规模相干运动的影响。然而，驱动这种运动的能源是与数百米尺度的对流运动有关的潜热加热。因此，对流和大尺度气流之间的双向相互作用是热带气象学的关键。相关的过程在广泛的时间和空间尺度上运作，也许部分由于这个原因，它们没有被用于天气和气候研究的数值模型很好地捕捉到。数值模式不能在所有的空间和时间尺度上明确地描述大气过程。相反，短尺度的运动必须通过使用参数化方案来考虑。一个模型将包含许多这样的方案，每一个方案都试图代表一个被忽略的特定小尺度过程对模型尺度的影响。这些过程包括大气边界层中的湍流、重力波和对流。云解析模式（CRM）是研究对流的有力工具。这种模型可用于执行高分辨率模拟，其中对流未被参数化，但被明确建模。参数化方案往往通过与CRM模拟结果的比较来开发和测试。然而，CRM模拟通常是通过规定大规模流通来设置的。因此，它们通常用于检查对流对预定义情况的响应。这样的模拟使对流和大尺度之间的明显区别。实际上，并没有如此明显的区别;事实上，对流和大尺度环流之间存在强烈的双向相互作用。因此，CRM模拟是过度约束：有限的，在他们可能的响应和不适合研究的相互作用mechanism.In最近几年，一些技术已经发展了近似的大尺度热带环流的响应与对流加热。这些近似值为模拟CRM内对流和大尺度环流之间的相互作用提供了基础。这意味着不再需要在模拟中指定大尺度，而是它将响应显式模拟的对流而演变。使用这些近似的研究产生了一些有价值的和有趣的结果。在这个项目中，我们将评估其中一些方法在热带对流中不同问题的相对优点，并利用它们来研究热带变率中对流和大尺度环流之间相互作用的作用。我们还将应用这个相同的框架来评估现有对流参数化方案的行为，为大气建模界提供了一个新的范例，以便对天气和气候模型进行精心控制和严格的测试。

项目成果

期刊论文数量（7）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Intercomparison of methods of coupling between convection and large-scale circulation: 2. Comparison over nonuniform surface conditions

对流与大范围环流耦合方法对比：2.非均匀地表条件比较

DOI：
10.7916/d8-atmj-2n24
发表时间：
2016
期刊：
影响因子：
0
作者：
Daleu C
通讯作者：
Daleu C

Using the Weak-Temperature Gradient Approximation to Evaluate Parameterizations: An Example of the Transition From Suppressed to Active Convection

使用弱温度梯度近似来评估参数化：从抑制对流到主动对流过渡的示例

DOI：
10.1002/2017ms000940
发表时间：
2017
期刊：
Journal of Advances in Modeling Earth Systems
影响因子：
6.8
作者：
Daleu C
通讯作者：
Daleu C

Influences of Local and Remote Conditions on Tropical Precipitation and Its Response to Climate Change

局地和远地条件对热带降水的影响及其对气候变化的响应

DOI：
10.1175/jcli-d-19-0450.1
发表时间：
2020
期刊：
Journal of Climate
影响因子：
4.9
作者：
Saint-Lu M
通讯作者：
Saint-Lu M

Intercomparison of methods of coupling between convection and large-scale circulation: 1. Comparison over uniform surface conditions.

对流与大范围环流耦合方法对比： 1、均匀地表条件下的对比。

DOI：
10.1002/2015ms000468
发表时间：
2015-12
期刊：
JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS
影响因子：
6.8
作者：
Daleu, C. L.;Plant, R. S.;Woolnough, S. J.;Sessions, S.;Herman, M. J.;Sobel, A.;Wang, S.;Kim, D.;Cheng, A.;Bellon, G.;Peyrille, P.;Ferry, F.;Siebesma, P.;van Ulft, L.
通讯作者：
van Ulft, L.

The Implications of an Idealized Large-Scale Circulation for Mechanical Work Done by Tropical Convection

理想化大规模循环对热带对流机械功的影响