Abstract The detailed evolution of different tropical tropopause layer (TTL) parameters, such as tropopause height (cold point (CPH)/lapse rate (LRH)/convective (COH)), its corresponding temperature (CPT/LRT/COT) and TTL thickness in response to recent 2015–16 El Nino event are delineated using high-resolution Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) Radio Occultation (RO) measurements. Distinct TTL anomalies are noticed between June-July-August (JJA), September-October-November (SON), and December -January-February (DJF) seasons during 2015–16 El Nino event. A pronounced positive anomaly in the CPH and LRH (∼0.8 km) is noticed in JJA over most of the tropical equatorial region, whereas, in DJF, positive anomalies mostly concentrate over off equatorial central Pacific (CP) and eastern Pacific (EP) regions. Interestingly, prominent higher positive anomalies are evident in the convective outflow level altitude (∼1 km) particularly over the tropical CP and EP regions in JJA and DJF. The CPT and LRT exhibit strong negative anomalies (>4 K) over CP and EP regions and positive anomalies over the western Pacific region in all the seasons. However, significant positive CPT and LRT anomalies are evident over the Atlantic region in DJF. In contrast, the COH (COT) and TTL thickness anomalies are well-matched with the outgoing long wave radiation anomalies compared to the CPH and LRH (CPT and LRT) anomalies. Overall, the observed TTL parameters exhibit similar El Nino signatures as observed for the other events. However, the 2015–16 El Nino event was one of strongest summer ENSO events in the 21st century compared to the previous events. As a result, prominent warm tropopause temperatures are evident over the WP region during JJA and these anomalies reaches maximum in DJF. The observed changes in the TTL parameters are explained in the context of circulation and convection changes over the tropics.

中文翻译：

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从 COSMIC RO 测量推断出的 2015-16 年厄尔尼诺事件期间的热带对流层顶层演化

摘要 对流层顶高度（冷点（CPH）/递减率（LRH）/对流（COH））、对应温度（CPT/LRT/COT）和TTL厚度等不同热带对流层顶层（TTL）参数的详细演化为了响应最近的 2015-16 年厄尔尼诺事件，我们使用高分辨率气象、电离层和气候星座观测系统 (COSMIC) 无线电掩星 (RO) 测量来描绘。在 2015-16 年厄尔尼诺事件期间，6-7-8 月 (JJA)、9-10-11 月 (SON) 和 12-1-2 月 (DJF) 季节之间会发现明显的 TTL 异常。在 JJA 的大部分热带赤道地区，CPH 和 LRH（~0.8 公里）有明显的正异常，而在 DJF，正异常主要集中在赤道中太平洋 (CP) 和东太平洋 (EP) 地区. 有趣的是，在对流流出水平高度（~1 公里）特别是在 JJA 和 DJF 的热带 CP 和 EP 区域上，明显的更高的正异常明显。CPT和LRT在CP和EP地区表现出强烈的负异常（> 4 K），在所有季节在西太平洋地区表现出正异常。然而，在 DJF 的大西洋地区，明显的正 CPT 和 LRT 异常是明显的。相比之下，与 CPH 和 LRH（CPT 和 LRT）异常相比，COH (COT) 和 TTL 厚度异常与出射长波辐射异常匹配良好。总体而言，观察到的 TTL 参数表现出与观察到的其他事件类似的厄尔尼诺特征。然而，与之前的事件相比，2015-16 年厄尔尼诺事件是 21 世纪最强的夏季 ENSO 事件之一。因此，在 JJA 期间，WP 区域明显存在明显的暖对流层顶温度，并且这些异常在 DJF 中达到最大值。观察到的 TTL 参数变化是在热带环流和对流变化的背景下解释的。