Dominant modes of wintertime precipitation variability in northwest China and the association with circulation anomalies and sea surface temperature

2020

Journal of Climate

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The present study investigates the interdecadal changes in the relationship between El Niño–Southern Oscillation (ENSO) and midlatitude North Atlantic (MNA) sea surface temperature (SST) with northwest China (NWC) winter precipitation (WP) variability and the plausible causes. Results show that ENSO and MNA SST have weak correlations with NWC WP before the mid-1990s, whereas the connections are enhanced sharply afterward, with above (below) normal precipitation occuring when there are positive (negative) ENSO SST and negative (positive) MNA SST anomalies (SSTA). Remarkable differences are found in the atmospheric circulations. After the mid-1990s, there is a pronounced Pacific–North American–Eurasian (PNA-EU)-like pattern in the Northern Hemisphere, whereas an Arctic Oscillation–like pattern is found before the mid-1990s. The change in the relationships between NWC WP and SSTs is likely attributable to the enhanced connection between ENSO and MNA SST after the mid-1990s. It is found that ENSO and MNA SSTA can cause NWC WP variation independently through atmospheric teleconnections. In addition, significant precipitation anomalies also occur when concurrent but oppositely signed SSTs anomalies in the two regions are observed. The reinforced negative correlations between ENSO and MNA SST after the mid-1990s act in concert on NWC WP by exciting a PNA-EU-like pattern. This information would help us to better understand the physical processes of the teleconnections between NWC WP variability and the ENSO/MNA SST, in which the strength of the correlation between ENSO and MNA SST should be taken into account.

Section: Interdecadal Change In the Relationships Between Nwc Wp And supporting

confidence: 91%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 91%

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Strengthened Relationships of Northwest China Wintertime Precipitation with ENSO and Midlatitude North Atlantic SST since the Mid-1990s

Yin

2020

Journal of Climate

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“…The uniform change in winter precipitation over NWC in the late 1980s represents the leading EOF mode of NWC winter rainfall anomalies (Yin and Zhou, 2018). However, some studies have suggested an opposite change in winter precipitation in the western and eastern areas of NWC (e.g., Song and Zhang, 2003).…”

Section: Summary and Discussionmentioning

confidence: 99%

Enhanced moisture transport associated with the interdecadal change in winter precipitation over Northwest China

Yin

Intl Journal of Climatology

2021

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In this study, the interdecadal increase in winter precipitation in northwest China (NWC) since the late 1980s and the associated moisture flux transport are investigated. The results show that an interdecadal change in moisture flux transport also occurred in the late 1980s, resulting in anomalous moisture transport convergence over NWC. The examination of boundary moisture transport shows enhanced incoming net moisture flux transport over NWC after the late 1980s. The zonal and meridional components both play a key role in the net moisture flux transport, with increased incoming transport from the western boundary dominated and followed by increased incoming transport from the southern boundary. The circulation responsible for the moisture flux transport anomalies is a Eurasian (EU)‐like teleconnection over mid‐to‐high latitudes of the Eurasian continent. The EU teleconnection pattern transformed from a positive phase to a negative phase in the late 1980s. The related anomalous cyclone over central Asia and the anomalous anticyclone over Japan result in westerly anomalies to the west of NWC and southeasterly anomalies to the east, respectively. Together, these anomalies enable an enhanced net gain of moisture transport and the anomalous moisture transport convergence over NWC. The enhanced moisture supply, strengthened upward movement and anomalous convergence result in an interdecadal increase in winter precipitation in NWC. In addition, the transition of the EU teleconnection is likely attributed to changes in the zonal mean wind. Sea surface temperature warming in the North Atlantic and northwestern Pacific regions also play a role in the change in the EU teleconnection pattern.

“…Understanding precipitation variability as well as its association with teleconnections is beneficial for a better adaptation to varying climatic conditions and a reduction in the damage related to climate change. The annual and interannual-to-decadal teleconnections (or oscillations) are often regarded as two of the most notable patterns and explanatory variables of climatic and hydrological variability (e.g., Hua et al, 2019;Lee et al, 2018;Li et al, 2018;Murgulet et al, 2017;Yin & Zhou, 2018). Valdés-Pineda et al (2018) adopted Singular Spectrum Analysis techniques to analyze the combined influence of two teleconnections on the variability of monthly precipitation in Chile.…”

mentioning

confidence: 99%

Detection and Attribution of Norwegian Annual Precipitation Variability Related to Teleconnections

Earth and Space Science

Ruan

et al. 2022

Detection and attribution of precipitation variability are fundamentally challenging, especially in the presence of complex nonlinear relationships between precipitation variability and large‐scale teleconnections. The aim of this study is twofold. First, we identify abrupt changes and the trend and periodicity characteristics of long‐term (1950–2019) annual precipitation series over the Norway mainland by using the Multiple Comparison Procedures, the Mann‐Kendall test, and the Wavelet Analysis. Second, we interpret the variability characteristics found over five regions of Norway by exploring their relationships with teleconnections through the Maximal Information Coefficient. The results indicate that significant abrupt changes appeared in the mean (variance) value of annual precipitation series at 117 (49) out of 159 rainfall stations of five regions in Norway at a significance level of 0.05. The occurrences of change points varied from 1979 to 1984 in five regions of Norway. The mean and variance of the annual precipitation series increased by 32% and 16% at most, respectively, compared with those values before the change points. The first periodicity (spanning four to five decades) was the dominant periodic component and could be used to best characterize the Norwegian precipitation variability. Because the subtropical Azores High (subpolar Icelandic Low) moves toward (away from) Europe, the relationship between the annual precipitation series and the Scandinavian pattern (Atlantic Multidecadal Oscillation) series tended to be of an upward (downward) hook structure. The association of precipitation variability and teleconnections found in this study can pave the way for new possibilities with regard to detection and attribution of precipitation variability.