scholarly journals Contribution of Tropical Cyclones to Rainfall at the Global Scale

2017 ◽  
Vol 30 (1) ◽  
pp. 359-372 ◽  
Author(s):  
Abdou Khouakhi ◽  
Gabriele Villarini ◽  
Gabriel A. Vecchi
Keyword(s):  
East Asia ◽  
Tropical Cyclones ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Extreme Rainfall ◽  
Annual Rainfall ◽  
Boreal Summer ◽  
Western Coast ◽  
Daily Precipitation Data

This study quantifies the relative contribution of tropical cyclones (TCs) to annual, seasonal, and extreme rainfall and examines the connection between El Niño–Southern Oscillation (ENSO) and the occurrence of extreme TC-induced rainfall across the globe. The authors use historical 6-h best-track TC datasets and daily precipitation data from 18 607 global rain gauges with at least 25 complete years of data between 1970 and 2014. The highest TC-induced rainfall totals occur in East Asia (>400 mm yr−1) and northeastern Australia (>200 mm yr−1), followed by the southeastern United States and along the coast of the Gulf of Mexico (100–150 mm yr−1). Fractionally, TCs account for 35%–50% of the mean annual rainfall in northwestern Australia, southeastern China, the northern Philippines, and Baja California, Mexico. Seasonally, between 40% and 50% of TC-induced rain is recorded along the western coast of Australia and in islands of the south Indian Ocean in the austral summer and in East Asia and Mexico in boreal summer and fall. In terms of extremes, using annual maximum and peak-over-threshold approaches, the highest proportions of TC-induced rainfall are found in East Asia, followed by Australia and North and Central America, with fractional contributions generally decreasing farther inland from the coast. The relationship between TC-induced extreme rainfall and ENSO reveals that TC-induced extreme rainfall tends to occur more frequently in Australia and along the U.S. East Coast during La Niña and in East Asia and the northwestern Pacific islands during El Niño.

scholarly journals The Impact of Tropical Cyclones on Extreme Precipitation over Coastal and Inland Areas of China and Its Association to ENSO

2018 ◽  
Vol 31 (5) ◽  
pp. 1865-1880 ◽  
Author(s):  
Qiang Zhang ◽  
Xihui Gu ◽  
Jianfeng Li ◽  
Peijun Shi ◽  
Vijay P. Singh
Keyword(s):  
Tropical Cyclones ◽  
El Niño ◽  
Extreme Precipitation ◽  
El Nino ◽  
Southern Oscillation ◽  
Reanalysis Dataset ◽  
Extreme Precipitation Events ◽  
Eastern Equatorial Pacific ◽  
Daily Precipitation Data ◽  
The Impact

The coastal part of China and its surrounding regions are dominated by a highly dense population and highly developed economy. Extreme precipitation events (EPEs) cause a lot of damage and hence changes in these events and their causes have been drawing considerable attention. This study investigated EPEs resulting from western North Pacific (WNP) tropical cyclones (TCs) and their potential link to El Niño–Southern Oscillation (ENSO), using TC track data, daily precipitation data from 2313 stations for 1951–2014, and the NCAR–NCEP reanalysis dataset. Two types of EPEs were considered: EPEs within 500 km from the TC center, and those caused by mesoscale and synoptic systems, referred to as predecessor rain events (PREs), beyond 1000 km from the TC center. Results indicated significant impacts of TCs on EPEs along the coastal areas, and discernable effects in inland areas of China. However, the effect of TCs on EPEs tended to be modulated by ENSO. During neutral years, inland areas of China are more affected by TC-induced extreme precipitation than during El Niño or La Niña years, with the highest density of TC tracks and larger-than-average numbers of tropical storms, typhoons, and landfalling TCs. During the El Niño phase, the central and eastern equatorial Pacific was characterized by higher sea surface temperature (SST), greater low-level vorticity (1000 hPa) and upper-level divergence (250 hPa), and stronger prevailing westerlies, which combined to trigger the movement of mean genesis to the eastern and southeastern WNP, resulting in fewer TCs passing through the Chinese territory.

scholarly journals Impacts of ENSO On The Seasonal Transition From Summer to Winter in East Asia

2021 ◽  
Author(s):  
Sunyong Kim ◽  
Jong-Seong Kug
Keyword(s):  
East Asia ◽  
El Niño ◽  
North Pacific ◽  
El Nino ◽  
Southern Oscillation ◽  
Temperature Drop ◽  
La Niña ◽  
Boreal Summer ◽  
Seasonal Transition ◽  
La Nina

Abstract The El Niño-Southern Oscillation (ENSO) has seasonally distinct impacts on the East Asian climate so that its seasonal transition depends on the phases of El Niño and La Niña. Here, we investigate the seasonal transition of surface temperature in East Asia from boreal summer to winter based on the warm/cold ENSO developing phases. During La Niña years, from summer to winter the continuous temperature drop in East Asia tends to be faster than that during El Niño, indicating a latter start and earlier termination of fall. This different seasonal transition in East Asia according to phases of ENSO is mostly explained by atmospheric responses to the seasonally-dependent tropical/subtropical precipitation forcings in ENSO developing phases. The anomalous positive precipitation in the subtropical North Pacific exists only in September and leads to the subtropical cyclonic flow during El Niño years. The resultant northerly anomalies on the left side of subtropical cyclone are favorable for transporting cold advection towards East Asia. However, the positive subtropical precipitation disappears and teleconnection to East Asia is strongly controlled by the negative precipitation anomalies in the western North Pacific, modulating the anticyclonic anomalies in East Asia during the early winter (November). Therefore, these seasonally sharp precipitation changes associated with ENSO evolution induce distinctive teleconnection changes from northerly (summer) to southerly (winter) anomalies, which eventually affect seasonal transition in East Asia. Also, the Coupled Model Intercomparison Project Phase 5 models reasonably simulate the relatively rapid temperature transition in East Asia during La Niña years, supporting the observational argument.

scholarly journals Determination of a New Coastal ENSO Oceanic Index for Northern Peru

Climate ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 71
Author(s):  
Edgard Gonzales ◽  
Eusebio Ingol
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Extreme Rainfall ◽  
Polynomial Equation ◽  
Extreme Rainfall Events ◽  
Emergency Operations Center ◽  
The Pacific ◽  
Northern Portion ◽  
Sequential Generation

In 2017, extreme rainfall events occurred in the northern portion of Peru, causing nearly 100,000 victims, according to the National Emergency Operations Center (COEN). This climatic event was attributed to the occurrence of the El Niño Southern Oscillation (ENSO). Therefore, the main objective of this study was to determine and differentiate between the occurrence of canonical ENSO, with a new type of ENSO called “El Niño Costero” (Coastal El Niño). The polynomial equation method was used to analyze the data from the different types of existing ocean indices to determine the occurrence of ENSO. It was observed that the anomalies of sea surface temperature (SST) 2.5 °C (January 2016) generated the “Modoki El Niño” and that the anomaly of SST −0.3 °C (January 2017) generated the “Modoki La Niña”; this sequential generation generated El Niño Costero. This new knowledge about the sui generis origin of El Niño Costero, based on the observations of this analysis, will allow us to identify and obtain important information regarding the occurrence of this event. A new oceanic index called the Pacific Regional Equatorial Index (PREI) was proposed to follow the periodic evolution and forecast with greater precision a new catastrophic event related to the occurrence of El Niño Costero and to implement prevention programs.

scholarly journals Effects of Tropical Cyclones on ENSO

2019 ◽  
Vol 32 (19) ◽  
pp. 6423-6443 ◽  
Author(s):  
Tao Lian ◽  
Jun Ying ◽  
Hong-Li Ren ◽  
Chan Zhang ◽  
Ting Liu ◽  
...  
Keyword(s):  
Tropical Cyclones ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Heat Content ◽  
Coupled Model ◽  
Enso Event ◽  
Central Pacific ◽  
Final State ◽  
Enso Dynamics

AbstractNumerous studies have investigated the role of El Niño–Southern Oscillation (ENSO) in modulating the activity of tropical cyclones (TCs) in the western Pacific on interannual time scales, but the effects of TCs on ENSO are less discussed. Some studies have found that TCs sharply increase surface westerly anomalies over the equatorial western–central Pacific and maintain them there for a few days. Given the strong influence of equatorial surface westerly wind bursts on ENSO, as confirmed by much recent literature, the effects of TCs on ENSO may be much greater than previously expected. Using recently released observations and reanalysis datasets, it is found that the majority of near-equatorial TCs (simply TCs hereafter) are associated with strong westerly anomalies at the equator, and the number and longitude of TCs are significantly correlated with ENSO strength. When TC-related wind stresses are added into an intermediate coupled model, the simulated ENSO becomes more irregular, and both ENSO magnitude and skewness approach those of observations, as compared with simulations without TCs. Adding TCs into the model system does not break the linkage between the heat content anomaly and subsequent ENSO event in the model, which manifest the classic recharge–discharge ENSO dynamics. However, the influence of TCs on ENSO is so strong that ENSO magnitude and sometimes its final state—that is, either El Niño or La Niña—largely depend on the number and timing of TCs during the event year. Our findings suggest that TCs play a prominent role in ENSO dynamics, and their effects must be considered in ENSO forecast models.

The North Pacific Pacemaker Effect on Historical ENSO and Its Mechanisms

2019 ◽  
Vol 32 (22) ◽  
pp. 7643-7661 ◽  
Author(s):  
Dillon J. Amaya ◽  
Yu Kosaka ◽  
Wenyu Zhou ◽  
Yu Zhang ◽  
Shang-Ping Xie ◽  
...  
Keyword(s):  
El Niño ◽  
North Pacific ◽  
El Nino ◽  
Southern Oscillation ◽  
Deep Convection ◽  
Boreal Summer ◽  
Enso Events ◽  
The North ◽  
The North Pacific

Abstract Studies have indicated that North Pacific sea surface temperature (SST) variability can significantly modulate El Niño–Southern Oscillation (ENSO), but there has been little effort to put extratropical–tropical interactions into the context of historical events. To quantify the role of the North Pacific in pacing the timing and magnitude of observed ENSO, we use a fully coupled climate model to produce an ensemble of North Pacific Ocean–Global Atmosphere (nPOGA) SST pacemaker simulations. In nPOGA, SST anomalies are restored back to observations in the North Pacific (>15°N) but are free to evolve throughout the rest of the globe. We find that the North Pacific SST has significantly influenced observed ENSO variability, accounting for approximately 15% of the total variance in boreal fall and winter. The connection between the North and tropical Pacific arises from two physical pathways: 1) a wind–evaporation–SST (WES) propagating mechanism, and 2) a Gill-like atmospheric response associated with anomalous deep convection in boreal summer and fall, which we refer to as the summer deep convection (SDC) response. The SDC response accounts for 25% of the observed zonal wind variability around the equatorial date line. On an event-by-event basis, nPOGA most closely reproduces the 2014/15 and the 2015/16 El Niños. In particular, we show that the 2015 Pacific meridional mode event increased wind forcing along the equator by 20%, potentially contributing to the extreme nature of the 2015/16 El Niño. Our results illustrate the significant role of extratropical noise in pacing the initiation and magnitude of ENSO events and may improve the predictability of ENSO on seasonal time scales.

scholarly journals El Niño effects on rainfall in South America: comparison with rainfalls in india and other parts of the world

2006 ◽  
Vol 6 ◽  
pp. 35-41 ◽  
Author(s):  
R. P. Kane
Keyword(s):  
South America ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Major Effect ◽  
Eastern Coast ◽  
Western Coast ◽  
Central Brazil ◽  
The Andes ◽  
Almost All

Abstract. As a finer classification of El Niños, ENSOW were defined as years when El Niño (EN) existed on the Peru coast, Southern Oscillation Index SOI (Tahiti minus Darwin pressure) was negative (SO), and Pacific SST anomalies were positive (W). Further, Unambiguous ENSOW were defined as years when SO and W occurred in the middle of the calendar year, while Ambiguous ENSOW were defined as years when SO and W occurred in the earlier or later part of the calendar year (not in the middle). In contrast with India and some other regions where Unambiguous ENSOW were associated predominantly with droughts, in the case of South America, the association was mixed. In Chile on the western coast and Uruguay etc. on the eastern coast, the major effect was of excessive rains. In Argentina and central Brazil, the effects were unclear. In Amazon, the effects were not at all uniform, and were different (droughts or excess rains) or even absent in regions only a few hundred kilometers away from each other. Even in Peru-Ecuador, the effects were clear only in the coastal regions. In the interior and in the Andes, the effects were obscure. In NE Brazil, El Niños have been popularly known to be causing severe droughts. The fact is that during 1871–1998, there were 52 El Niño events, out of which 31 were associated with droughts in NE Brazil, while 21 had no association. The reason is that besides El Niños, another major factor affecting NE Brazil is the influx of moisture from the Atlantic. In some years, warmer Atlantic in conjunction with westward winds can bring moisture to NE Brazil, nullifying the drought effects of El Niños. A curious feature at almost all locations is the occurrence of extreme events (high floods or severe droughts) in some years, apparently without any El Niño or La Niña events. This possibility should always be borne in mind.

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