WCRP and WWRP THORPEX YOTC (Year of Tropical Convection) Project, Single Parameter 6-Hourly Surface Analysis and Surface Forecast Time Series, Transformed to a Regular 1600 by 800 (N400) Gaussian Grid

The realistic representation of tropical convection in our global atmospheric models is a long-standing grand challenge for numerical weather forecasts and global climate predictions. Our lack of fundamental knowledge and practical capabilities in this area leaves us disadvantaged in modeling and predicting prominent phenomena of the tropical atmosphere such as the ITCZ, ENSO, TBO, monsoons and their active or break periods, the MJO, subtropical stratus decks, near-surface ocean properties, easterly waves, tropical cyclones, bulk budgets of cloud microphysical quantities, and even the diurnal cycle. Furthermore, tropical weather and climate disturbances strongly influence stratospheric-tropospheric exchange as well as the extratropics, with the later mediated via poleward migration of synoptic systems or through initiating Rossby wave trains that can involve a range of processes and time scales.

To address the challenge of tropical convection, WCRP and WWRP/THORPEX propose a Year of coordinated observing, modeling and forecasting of organized tropical convection and its influences on predictability as a contribution to the United Nations Year of Planet Earth to complement the International Polar Year (IPY). This effort is intended to exploit the vast amounts of existing and emerging observations, the expanding computational resources and the development of new, high-resolution modeling frameworks, with the objective of advancing the characterization, diagnosis, modeling, parameterization and prediction of multiscale convective and dynamic interactions, including the two-way interaction between tropical and extra-tropical weather or climate. This activity and its ultimate success will be based on the coordination of a wide range of ongoing and planned international programmatic activities (e.g., GEWEX/CEOP/GCSS, AMY, EOS, GOOS), strong collaboration among the operational prediction, research laboratory and academic communities, and the construction of a comprehensive data base consisting of satellite data, in-situ data sets and global, high-resolution forecast and simulation model outputs relevant to tropical convection. The proposed timing, focus year approach and integrated framework of this effort is intended to leverage the most benefit from recent investments in Earth Science infrastructure as well as entrain a new generation of young scientists into tackling the outstanding problems in the field of weather and climate prediction.

It is recommended that potential users of YOTC peruse the Related RDA Datasets ds629.1-ds629.6 (please see below) which represent transformed versions of the raw ECMWF YOTC archive (ds629.0) by the Data Support Section. The transformed versions are archived on an N400 1600 by 800 regular Gaussian grid, starting from high resolution reduced Gaussian grids and spectral coefficients. In addition, horizontal winds have been added and computed from spectral vorticity and divergence.

对热带对流在全局大气模型中的真实表征，长期以来一直是数值天气预报和全球气候预测领域的一项重大挑战。我们在这一领域的基本知识和实践能力方面的不足，使我们难以模拟和预测热带大气中的显著现象，如赤道辐合带、厄尔尼诺-南方涛动（ENSO）、热带波动（TBO）、季风及其活跃或间断期、季风振荡（MJO）、副热带层积云层、近海表面海洋特性、东风波、热带气旋、云微物理量的总量预算，乃至日变化周期。此外，热带天气和气候扰动对平流层-对流层交换以及中纬度地区有着显著影响，后者通过天气系统的极地向迁移或通过引发涉及多种过程和时间尺度的罗斯贝波列来介导。为应对热带对流的挑战，世界气候研究计划（WCRP）和世界天气研究计划/THORPEX提出了一项协调观测、建模和预测有组织热带对流及其对可预测性影响的年度计划，作为联合国地球年活动的一部分，以补充国际极年（IPY）。这一努力旨在充分利用现有和新兴的观测数据、不断扩大的计算资源以及新型高分辨率建模框架的发展，旨在推进多尺度对流和动力相互作用的特征化、诊断、建模、参数化和预测，包括热带与中纬度天气或气候之间的双向交互。这一活动的成功将基于对一系列正在进行和计划中的国际项目（例如，GEWEX/CEOP/GCSS、AMY、EOS、GOOS）的协调，以及预测、研究实验室和学术社区之间的紧密合作，以及构建一个综合数据库，包括卫星数据、现场数据集和与热带对流相关的全球、高分辨率预报和模拟模型输出。该提议的时间安排、重点年份方法和综合框架旨在最大限度地利用对地球科学基础设施的最新投资，并吸引新一代年轻科学家投身于解决天气和气候预测领域中的突出问题。建议潜在的用户查阅相关的RDA数据集ds629.1-ds629.6（请见下文），这些数据集代表了数据支持部门对原始ECMWF YOTC档案（ds629.0）的转换版本。转换版本存档在N400 1600×800的正则高斯网格上，从高分辨率减少高斯网格和谱系数开始，并增加了水平风速，该风速由谱涡度和散度计算得出。