Precipitation is an important climate quantity that is critically relevant to society. In spite of intense efforts, significant precipitation biases remain in most climate models. One pervasive and persistent bias found in many general circulation models occurs in the Tropical West Pacific where northern hemisphere summer‐time precipitation is often underestimated compared to observations. Using the DOE‐E3SM model, the inclusion of a missing process, convective gustiness, is shown to reduce those biases through a net increase in surface evaporation. Gustiness in surface wind fields is assumed to arise empirically in proportion to the intensity of convective precipitation. The increased evaporation can be treated as an increase in the moist static energy forcing into the atmosphere. A Normalized Gross Moist Stability (NGMS) framework (which characterizes the relationship between convective forcing and convective response) is used to explore the processes responsible for the precipitation bias, and the impact of the gustiness parameterization in reducing that bias. Because the NGMS of the Tropical West Pacific is less than unity in the E3SMv1 model, the increase in energy forcing amplifies the increase in precipitation to exceed that of the evaporative flux. Convective gustiness favors increased precipitation in regions where the resolved surface winds are weak and convection is present.

中文翻译：

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对流细气在减少热带西太平洋季节性降水偏向中的作用

降水是与社会息息相关的重要气候量。尽管付出了巨大的努力，但大多数气候模型中仍然存在明显的降水偏差。在许多普通环流模型中发现的普遍性和持续性偏差发生在热带西太平洋地区，与观测相比，该地区北半球的夏季降水经常被低估。使用DOE-E3SM模型，通过增加表面蒸发的净增加量，可以看到包括缺少的过程（对流阵风）可以减少这些偏差。假定表面风场中的阵风根据经验与对流降水强度成正比。蒸发的增加可以看作是强迫进入大气的潮湿静态能量的增加。使用归一化总湿润稳定性（NGMS）框架（描述了对流强迫和对流响应之间的关系）来探索造成降水偏差的过程以及阵风参数化对减少该偏差的影响。因为在E3SMv1模型中，热带西太平洋的NGMS小于1，所以能量强迫的增加会放大降水的增加，使其超过蒸发通量。对流阵风有利于在解决的地面风弱且存在对流的地区增加降水。因为在E3SMv1模型中，热带西太平洋的NGMS小于1，所以能量强迫的增加会放大降水的增加，使其超过蒸发通量。对流阵风有利于在解决的地面风弱且存在对流的地区增加降水。因为在E3SMv1模型中，热带西太平洋的NGMS小于1，所以能量强迫的增加会放大降水的增加，使其超过蒸发通量。对流阵风有利于在已解决的地面风弱且存在对流的地区增加降水。