Tracking mesoscale convective systems in central equatorial Africa
Tracking mesoscale convective systems in central equatorial Africa
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DOI：
10.1002/joc.6632
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发表时间：
2020-05-19
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影响因子：
--
通讯作者：
Hartman, Adam T.
中科院分区：
文献类型：
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作者：
Hartman, Adam T.
非洲赤道中部的刚果盆地是全球热带地区最强烈对流的所在地。中尺度对流系统 (MCS) 在 3 月至 4 月至 5 月 (MAM) 和 9 月至 10 月至 11 月 (SON) 雨季期间提供了该地区的大部分年降雨量。这些系统的特征对于该地区的降雨变化至关重要，并极大地影响人类健康、农业、畜牧业和干旱监测。由于缺乏现场观测和气象站，对变异性的了解受到阻碍。本研究确定并跟踪了 1983 年至 2015 年 33 年间 MAM 和 SON 的 MCS。使用卫星和再分析数据计算雨季的 MCS 和环境参数。将 MCS 参数的空间分布和选定 MCS 参数的昼夜周期与先前的研究进行了比较。进行统计显着性测试以确定季节之间是否存在有意义的差异。简要讨论了季节差异。 650 hPa 相对涡度模式表明，局部地形效应可能在东非大裂谷背风处的 MCS 起始频率接近局部最大值时发挥作用。基于起始位置的 33 年 MCS 计数、轨迹、速度、大小、最大强度和持续时间的空间分布与先前的研究非常吻合。季节之间的差异在统计上是显着的，并且随纬度的变化而变化。所有 MCS 和环境参数之间存在很大的年际变化。
The Congo basin in central equatorial Africa is home to some of the most intense convection in the global tropics. Mesoscale convective systems (MCSs) provide much of the annual rainfall over this region during the March-April-May (MAM) and September-October-November (SON) rainy seasons. Features of these systems are essential to rainfall variability in this region and greatly impact human health, agriculture, livestock, and drought monitoring. Knowledge of variability is hindered by the lack of in-situ observations and meteorological stations. The present study identifies and tracks MCSs for the 33-year period 1983-2015 for MAM and SON. MCS and environmental parameters are calculated for the rainy seasons using satellite and reanalysis data. Spatial distributions of MCS parameters and diurnal cycles for select MCS parameters are compared to prior research. Statistical significance testing is performed to determine if there are meaningful differences between the seasons. Seasonal differences are briefly discussed. 650 hPa relative vorticity patterns suggest localized terrain effects may play a role near a local maximum in MCS initiation frequency in the lee of the Great Rift Valley. Spatial distributions of 33-year MCS counts, trajectories, speeds, sizes, maximum intensities, and durations, based on initiation locations, agree well with prior research. Differences between seasons are statistically significant and variable and latitude dependent. There is high interannual variability among all MCS and environmental parameters.