The intensity of precipitation during extratropical cyclones in global warming simulations: a link to cyclone intensity?
The intensity of precipitation during extratropical cyclones in global warming simulations: a link to cyclone intensity?
复制标题
全球变暖模拟中温带气旋期间的降水强度：与气旋强度的联系？
DOI：
10.1111/j.1600-0870.2006.00147.x
复制
发表时间：
2006
期刊：
影响因子：
--
通讯作者：
I. Watterson
中科院分区：
文献类型：
--
作者：
I. Watterson
本文分析了两个CSIRO GCMs对未来一个世纪全球变暖的模拟，以评估温带气旋强度的变化，以及气旋期间与降水相关的潜热增加的潜在作用。在温室气体浓度上升的情况下，将一个简单的表面气旋检测方案应用于Mark 2 GCM的四成员模拟集合。1961-1990年气旋的季节分布大致符合实际情况。到2071-2100年，全球变暖3k， 20°N到70°N以上的数量冬季减少6%，年减少2%，南方也有类似的结果。然而，从相对中心压力和其他措施来看，气旋的平均强度基本上没有变化。30年极端动态强度也没有明显变化，包括各大洲的平均值。气旋中心的平均降雨率通常至少是全天降雨率的两倍。在全球变暖的影响下，北半球冬季的飓风发生率平均上升14%。相邻方格和前一天的发病率也有类似的增长，极端发病率也是如此。高分辨率（1.8◦栅格）mark3 GCM的模拟结果类似，降雨率普遍增加，但气旋强度没有增加。分析表明，风暴期间的潜热增加，正如预期的那样，由于较暖的大气增加了水分容量。然而，在gcm中，任何增强加热在风暴发展中的作用显然都被其他因素所掩盖。一个例外是5%的极端强度增加约55◦S在马克3，尽管减少了低的数量，一个因素评估使用极值理论。可能需要使用更高分辨率的模型进行进一步研究，以检验这些结果的潜在真实性，特别是在较小尺度上的极端情况。
Simulations of global warming over the coming century from two CSIRO GCMs are analysed to assess changes in the intensity of extratropical cyclones, and the potential role of increased latent heating associated with precipitation during cyclones. A simple surface cyclone detection scheme is applied to a four-member ensemble of simulations from the Mark 2 GCM, under rising greenhouse gas concentrations. The seasonal distribution of cyclones appears broadly realistic during 1961–1990. By 2071–2100, with 3 K global warming, numbers over 20◦N to 70◦N decrease by 6% in winter and 2% annually, with similar results for the south. The average intensity of cyclones, from relative central pressure and other measures, is largely unchanged however. 30-yr extremes of dynamic intensity also show little clear change, including values averaged over continents. Mean rain rates at cyclone centres are typically at least double rates from all days. Rates during cyclones increase by an average 14% in the northern winter under global warming. Rates over adjacent grid squares and during the previous day increase similarly, as do extreme rates. Results from simulations of the higher-resolution (1.8◦ grid) Mark 3 GCM are similar, with widespread increases in rain rates but not in cyclone intensity. The analyses suggest that latent heating during storms increases, as anticipated due to the increased moisture capacity of the warmer atmosphere. However, any role for enhanced heating in storm development in the GCMs is apparently masked by other factors. An exception is a 5% increase in extreme intensity around 55◦S in Mark 3, despite decreased numbers of lows, a factor assessed using extreme value theory. Further studies with yet higher-resolution models may be needed to examine the potential realism of these results, particularly with regard to extremes at smaller scale.