Decadal winter drought in Southwest China since the late 1990s and its atmospheric teleconnection

Abstract

The extreme drought in Southwest China (SWC) during the winter 2009/2010 brought catastrophic losses to the state and people. In this article, evidence has been presented that this drought event was not a single one but part of a decade‐long drying period after 2000. Based on observed data from meteorological stations, we identified two distinct modes of winter precipitation in SWC: one is spatially in‐phase change pattern and the other is east–west dipole pattern, both of which experienced a sharp decadal decrease since the late 1990s. The two modes are closely linked to two atmospheric circulation patterns induced by Arctic Oscillation (AO) and El Niño, respectively. The sustained precipitation deficit in SWC after 2000 was associated with the anomalous atmospheric circulation patterns mainly caused by the decadal transition of AO towards its negative phases and frequent El Niño, especially the central Pacific El Niño. The model experiments forced by sea surface temperature anomaly patterns in the North Atlantic (NA) and tropical Pacific (TP), respectively, could robustly reproduce precipitation anomaly in SWC and large‐scale circulation pattern. The NA SST could excite a series of quasi‐stationary wave trains, which propagate eastward to the south of the Himalayas, similar to the AO‐related teleconnection. The SWC is just beneath the anti‐cyclonic circulation anomaly with dry conditions. In the TP experiment, the simulated ascending motion locates over the central Pacific, while the anomalous descending branch of the western Walker cell appears over the SWC, being not conducive to the formation of precipitation.

Estimating Trends and Return Periods of Daily Extreme Precipitation Associated with Tropical Cyclones in the Core North American Monsoon

“…These five hurricanes were Lidia (September [8][9][10][11][12][13][14]1993, which occurred during a neutral event), Ismael (September 12-15, 1995, during a neutral event), Fausto (September [10][11][12][13][14]1996, during a neutral event), and Isis (September 1-3, 1998, during a La Niña event), and only one cyclone event in the period September 18-30, 1982, which occurred during a strong summer El Niño. These results are similar to those reported by [33,39], who found that there was a strong El Niño event in 1982 and La Niña events in late 1990. They also claim that extreme daily precipitation in a region tends to increase from anomalous effects in a La Niña event and not so much in an El Niño.…”

“…This transformed the 1990s into one of the more prolific decades in history, which is documented in previous piezometer studies in the region [38]. Of 13 TCs recorded in the study area during the summer in the period 1961-2000, five made landfall and four occurred in the 1990s [39]. The effects of hurricanes with increasing precipitation, trends which have been identified in the period 1981-2000, were also reported by [40]: "Hurricanes of major intensity contributed in irrigation districts 063 and 065 with a hydraulic loading of 25 m, which was registered for the first time in 30 years with a recovery of 1.2 m in the 1990s."…”

“…3c), thus increasing the magnitude of land-sea thermal contrast, which in turn increases the availability of moisture (Fig. 3d) for a distribution of storms along the Mexican Pacific [5,39,42]. The positive anomalies of Stemp an (>0.5ºC) in northwestern Mexico suggest a positive land-sea thermal contrast [3,45] (Figs 3e-f).…”

Long‐term change of potential evapotranspiration over southwest China and teleconnections with large‐scale climate anomalies

“…Tan et al . () found the sustained precipitation (PRE) deficit in this area after 2000 was associated with the anomalous atmospheric circulation patterns mainly caused by the decadal transition of Arctic Oscillation and El Nino. However, the related atmospheric background fields and its changing characteristics on PET over southwest China have not been clearly understood.…”

Complex Networks Reveal Teleconnections between the Global SST and Rainfall in Southwest China

“…Pacific and North Atlantic SST in dry season (JFM). A series of recent drought events were studied in SWC after 1990s (Tan et al, 2017). They found that both the Arctic Oscillation and the South Oscillation strongly influence rainfall of SWC.…”