Examining the Role of the Land Surface on Convection Using High‐Resolution Model Forecasts Over the Southeastern United States
Examining the Role of the Land Surface on Convection Using High‐Resolution Model Forecasts Over the Southeastern United States
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DOI：
10.1029/2022jd036563
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发表时间：
2022-08
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影响因子：
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通讯作者：
David S. Henderson;J. Otkin;J. Mecikalski
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作者：
David S. Henderson;J. Otkin;J. Mecikalski
利用GOES-16的红外亮温(BT)资料，研究了统一的NOAH和NOAH-MP陆面模式(LSM)对达到对流起始(CI)的积云演变的影响。利用高分辨率(500m水平网格间距)模式的模拟结果，检验了单个云体的云特性。随着时间的推移，云对象被跟踪，并与达到CI的观察到的云相关联，以检查云范围、寿命和增长率的差异。结果表明，假设地表性质的不同可以导致地面净辐射收支的差异，特别是在差异超过40W m−2的感热和潜热分量上。这些差异导致局地中尺度环流型的变化，这种变化在低层辐合较强的森林和草原边界附近更为明显。来自NOAH-MP LSM的较高的感热使CI云的增长更早且持续时间更长，这更接近于从GOES-16观测到的时间和增长。NOAH-MP实验中云增长的增加是由于更强和更深的上升气流，它将更多的云水送入对流层上层。来自Noah LSM实验的较弱上升气流导致CI被探测到后，由于增长速度较慢，导致对流变浅。云的性质和增长的差异与它们在上面发展的地面直接相关，并表明在数值天气预报模式中模拟对流时，准确地表示地面性质和辐射特征的重要性。
The influence of the Unified Noah and Noah‐MP land surface models (LSMs) on the evolution of cumulus clouds reaching convective initiation (CI) is assessed using infrared brightness temperatures (BT) from GOES‐16. Cloud properties from individual cloud objects are examined using output from high‐resolution (500 m horizontal grid spacing) model simulations. Cloud objects are tracked over time and related to observed clouds reaching CI to examine differences in cloud extent, longevity, and growth rate. The results demonstrate that differences in assumed surface properties can lead to large discrepancies in the net surface radiative budget, particularly in the sensible and latent heating components where differences exceed 40 W m−2. These differences lead to changes in the local mesoscale circulation patterns that are more pronounced near the edges of forested and grassland boundaries where lower‐level convergence is stronger. Higher sensible heating from the Noah‐MP LSM produced growth of CI clouds earlier and with increased longevity, which was closer to the timing and growth observed from GOES‐16. The increased cloud growth in the Noah‐MP experiment results from stronger and deeper updrafts, which lofts more cloud water into the upper levels of the troposphere. The weaker updrafts from the Noah LSM experiment results in shallower convection after CI is detected due to slower growth rates. The differences in cloud properties and growth are directly related to the land surfaces they develop above and point to the importance of accurately representing land properties and radiative characteristics when simulating convection in numerical weather prediction models.