An Evaluation of Simulated Precipitation Characteristics during OLYMPEX
An Evaluation of Simulated Precipitation Characteristics during OLYMPEX
复制标题
DOI：
10.1175/jhm-d-18-0144.1
复制
发表时间：
2019-06
影响因子：
3.8
通讯作者：
Robert Conrick;C. Mass
中科院分区：
文献类型：
--
作者：
Robert Conrick;C. Mass
OLYMPEX 实地活动于 2015/2016 年冬季在华盛顿州奥林匹克山周围进行，提供了用于评估该屏障上方和附近的模拟微物理和降水的数据。本文利用 OLYMPEX 观测结果评估了美国太平洋西北地区 WRF-ARW 模型中的降水和相关微物理。华盛顿大学实时 WRF 预报系统在 OLYMPEX 实地计划期间（2015 年 11 月至 2016 年 2 月）和较长时期（2008 年至 18 年）的降水模型显示，降水量持续低估，沿海地区迎风面降水量达到 100 毫米 yr−1。增加水平分辨率并不能显着减少这种低估。通过评估 2015/2016 OLYMPEX 冬季的地表测速仪观测结果，发现使用汤普森微物理的华盛顿大学 WRF 建模系统对迎风沿海山谷的雨滴尺寸分布的模拟效果不佳。尽管液态水含量被真实地表示，但雨滴直径被高估，因此，雨滴分布截距参数被低估。在两次强降水期间，WRF 真实地模拟了环境条件，包括风速、热力学结构、综合水分输送和融化水平。除了汤普森方案之外，还测试了几种微观物理参数化方案，每个方案都对这两个事件表现出相似的偏差。我们表明，西北沿海气溶胶的参数化仅提供了微小的改进。
The OLYMPEX field campaign, which took place around the Olympic Mountains of Washington State during winter 2015/16, provided data for evaluating the simulated microphysics and precipitation over and near that barrier. Using OLYMPEX observations, this paper assesses precipitation and associated microphysics in the WRF-ARW model over the U.S. Pacific Northwest. Model precipitation from the University of Washington real-time WRF forecast system during the OLYMPEX field program (November 2015–February 2016) and an extended period (2008–18) showed persistent underprediction of precipitation, reaching 100 mm yr−1 over the windward side of the coastal terrain. Increasing horizontal resolution does not substantially reduce this underprediction. Evaluating surface disdrometer observations during the 2015/16 OLYMPEX winter, it was found that the operational University of Washington WRF modeling system using Thompson microphysics poorly simulated the rain drop size distribution over a windward coastal valley. Although liquid water content was represented realistically, drop diameters were overpredicted, and, consequently, the rain drop distribution intercept parameter was underpredicted. During two heavy precipitation periods, WRF realistically simulated environmental conditions, including wind speed, thermodynamic structures, integrated moisture transport, and melting levels. Several microphysical parameterization schemes were tested in addition to the Thompson scheme, with each exhibiting similar biases for these two events. We show that the parameterization of aerosols over the coastal Northwest offered only minor improvement.