Dominant climatic factors controlling the lifetime peak intensity of typhoons are determined from six decades of Pacific typhoon data We find that upper ocean temperatures in the low-latitude northwestern Pacific (LLNWP) and sea surface temperatures in the central equatorial Pacific control the seasonal average lifetime peak intensity by setting the rate and duration of typhoon intensification, respectively An anomalously strong LLNWP upper ocean warming has favored increased intensification rates and led to unprecedentedly high average typhoon intensity during the recent global warming hiatus period, despite a reduction in intensification duration tied to the central equatorial Pacific surface cooling Continued LLNWP upper ocean warming as predicted under a moderate [that is, Representative Concentration Pathway (RCP) 45] climate change scenario is expected to further increase the average typhoon intensity by an additional 14% by 2100

Northwestern Pacific Typhoon Intensity Controlled by Changes in Ocean Temperatures

Los sistemas de pastizales tropicales de gran altitud, llamados Paramo, brindan servicios ecosistemicos esenciales como el almacenamiento y el suministro de agua para las areas circundantes y de tierras bajas. Los sistemas de paramo estan amenazados por los cambios climaticos y de uso del suelo. Los procesos de generacion de lluvia y las vias de transporte de humedad que influyen en la precipitacion en el Paramo no se conocen bien, pero se necesitan para estimar el impacto de estos cambios, particularmente durante las condiciones de El Nino, que afectan en gran medida las condiciones hidrometeorologicas en las regiones tropicales. Para llenar este vacio de conocimiento, presentamos un analisis de isotopos estables de las muestras de lluvia recolectadas diariamente o semanalmente entre enero de 2015 y mayo de 2016 durante el evento de El Nino mas fuerte registrado en la historia (2014-2016) en dos regiones de Paramo de America Central (Chirripo, Costa Rica) y el norte de los Andes (Cajas, sur de Ecuador). Se utilizaron composiciones isotopicas para identificar como los procesos de generacion de lluvia (convectiva y orografica) cambian estacionalmente en cada sitio de estudio. Se uso el analisis de trayectoria de masa de aire hibrido de modelo de trayectoria integrada lagrangiana de particula unica (HYSPLIT) para identificar rutas preferenciales de transporte de humedad a cada sitio de Paramo. Nuestros resultados muestran la fuerte influencia de los vientos alisios del noreste para transportar la humedad del Mar Caribe a Chirripo y el jet sudamericano de bajo nivel para transportar la humedad del bosque amazonico a Cajas. Estas contribuciones de humedad tambien se relacionaron con la formacion de lluvia convectiva asociada con el paso de la Zona de Convergencia Intertropical sobre Costa Rica y Ecuador durante las estaciones mas humedas y con la precipitacion orografica durante las temporadas de transicion y mas secas. Nuestros hallazgos brindan informacion basica esencial para futuras aplicaciones de investigacion de isotopos estables al agua como trazadores de procesos de generacion de lluvia y transporte en el Paramo y otros ecosistemas montanos en los tropicos.

Moisture transport and seasonal variations in the stable isotopic composition of rainfall in Central American and Andean Páramo during El Niño conditions (2015–2016)

Stable isotope ratios of typhoon rains in Fuzhou, Southeast China, during 2013–2017

Control of seasonal water vapor isotope variations at Lhasa, southern Tibetan Plateau

Improved High-Resolution Global and Regionalized Isoscapes of δ18O, δ2H, and d-Excess in Precipitation

Sumatra Squalls, organized bands of thunderstorms, are the dominant mesoscale convective systems during the inter-monsoon and Southwest Monsoon seasons in Singapore. To understand how they affect precipitation isotopes, we monitored the δ-value of precipitation daily and continuously (every second and integrated over 30 seconds) during all squalls in 2015. We found that precipitation δ18O values mainly exhibit a “V” shape pattern and less commonly a “W” shape pattern. Variation in δ18O values during a single event is about 1 to 6‰ with the lowest values mostly observed in the stratiform zone, which agrees with previous observations and modeling simulations. Re-evaporation can significantly affect δ-values, especially in the last stage of the stratiform zone. Daily precipitation is characterized by periodic negative shifts in δ-value, largely associated with squalls rather than moisture source change. The shifts can be more than 10‰, larger than intra-event variation. Initial δ18O values of events are highly variable, and those with the lowest values also have the lowest initial values. Therefore, past convective activities in the upwind area can significantly affect the δ18O, and convection at the sampling site has limited contribution to isotopic variability. A significant correlation between precipitation δ18O value and regional Outgoing Longwave Radiation and rainfall in the Asian monsoon region and western Pacific suggests that regional organized convection probably drives stable isotopic compositions of precipitation. A drop in the frequency of the squalls in 2015 is related to weak organized convection in the region caused by El Nino.

/pdf/stable-isotopes-of-precipitation-during-tropical-sumatra-1k57vk9465.pdf

Stable isotopes of precipitation during tropical Sumatra Squalls in Singapore

https://onlinelibrary.wiley.com/doi/pdf/10.1002/hyp.11520

Continuous real-time analysis of the isotopic composition of precipitation during tropical rain events: Insights into tropical convection

/pdf/understanding-tropical-convection-through-triple-oxygen-1062ep68y9.pdf

Understanding Tropical Convection Through Triple Oxygen Isotopes of Precipitation From the Maritime Continent

. Tropical cyclones have devastating impacts on the environment, economies, and societies, and may intensify in the coming decades due to climate change. Stable water isotopes serve as tracers of the hydrological cycle, as the fractionation process may leave distinct precipitation isotopic signatures. Here we present a record of daily precipitation isotope measurements from March 2014 to October 2015 for Metropolitan Manila, which is a first of a kind dataset for the Philippines and Southeast Asia, and analyze if there is an isotopic response to tropical cyclones. The most negative shift in δ18O value (−13.84 ‰) leading to a clear isotopic signal was caused by Typhoon Rammasun, which directly hit Metropolitan Manila. The average δ18O value of precipitation associated with tropical cyclones is −10.24 ‰, whereas the mean isotopic value for rainfall associated with non-cyclone events is −5.29 ‰. Further, the closer the storm track to the sampling site, the more negative the isotopic values, indicating that in-situ isotope measurements can provide a direct linkage between isotopes and typhoon activities in the Philippines.

/pdf/precipitation-stable-isotopic-signatures-of-tropical-2zspohigfi.pdf

Shaoneng He

Papers

Stable isotopes of precipitation during tropical Sumatra Squalls in Singapore

Continuous real-time analysis of the isotopic composition of precipitation during tropical rain events: Insights into tropical convection

Understanding Tropical Convection Through Triple Oxygen Isotopes of Precipitation From the Maritime Continent

Precipitation stable isotopic signatures of tropical cyclones in Metropolitan Manila, Philippines show significant negative isotopic excursions

Stable Isotopes of Daily Precipitation in Singapore (2013/2014): A Reflection of Moisture Source and Atmospheric Circulation