scholarly journals Climatic Controls and Hydrologic Impacts of a Recent Extreme Seasonal Precipitation Reversal in Arizona

2008 ◽  
Vol 47 (2) ◽  
pp. 498-508 ◽  
Author(s):  
Gregory B. Goodrich ◽  
Andrew W. Ellis
Keyword(s):  
El Niño ◽  
El Nino ◽  
Historical Context ◽  
Atlantic Multidecadal Oscillation ◽  
Winter Precipitation ◽  
Seasonal Precipitation ◽  
Time Period ◽  
Hydrologic Impacts ◽  
The 1960S ◽  
One Year

Abstract The winter (December–February) of 2005/06 ranked as the driest in the instrumental record (since 1895) for nearly all regions of Arizona. The city of Phoenix, Arizona, recorded no precipitation during this time period, which was part of a record dry streak of 143 days without measurable precipitation. More important, the Salt and Verde watersheds, which supply the greater Phoenix area with approximately 50% of its water supply, received less than 3% of normal precipitation. Remarkably, this historically dry winter was preceded by the second wettest winter on record in 2004/05, a winter that filled reservoirs statewide and ameliorated a drought that has persisted since 1996 in some parts of the state. This study begins with a brief overview of the historical context of such reversals of extreme seasonal precipitation in Arizona followed by an analysis of the teleconnective impacts. The authors find that while an extreme reversal such as this has only happened once before in Arizona (1904/05 and 1905/06), there is a trend for increasing variability in winter precipitation from one year to the next in Arizona, especially since the 1960s. Large reversals of winter precipitation are followed by large reversals of the opposite sign in the summer monsoon more than 75% of the time. In general, large dry-to-wet reversals are associated with neutral ENSO–to–neutral ENSO conditions or a neutral ENSO–to–El Niño transition, whereas wet-to-dry reversals are associated with an El Niño–to–La Niña transition or, more commonly, with an El Niño–to–neutral ENSO transition. In addition, changes in the sign of the Atlantic multidecadal oscillation, eastern Pacific oscillation, and Pacific–North American (PNA) pattern are all significantly associated with precipitation reversals. During the seven winters when neutral ENSO and strongly positive PNA coexist, large wet-to-dry reversals occur in every case and nearly all rank among the largest such reversals. It is suggested that small reservoirs are more at risk for increasing climatic volatility than are large reservoirs.

scholarly journals Variation in Seasonal Precipitation over Gaza (Palestine) and Its Sensitivity to Teleconnection Patterns

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 667
Author(s):  
Salah Basem Ajjur ◽  
Sami G. Al-Ghamdi
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Winter Precipitation ◽  
Climate Indices ◽  
Seasonal Precipitation ◽  
Teleconnection Patterns ◽  
Mitigation And Adaptation ◽  
Set Up ◽  
Mitigation And Adaptation Strategies

The seasonal precipitation (SP) trend and its sensitivity to teleconnection patterns over the East Mediterranean (EM) region remain inconsistent. Based on rainfall records during 1974–2016 at seven meteorological stations in the Gaza region, this study aims to (1) analyze the observed SP trend over the Gaza region, and (2) examine the SP sensitivity to climate indices. Pearson and Spearman correlations between climate indices and SP in the current and following years were calculated, and the seasonal period (particular month) with the highest correlation was identified. Results show that the climate indices, with greater impact on SP over the Gaza region in the autumn and spring, were in the order; El Niño-Southern Oscillation (ENSO) > East Atlantic/Western Russia (EAWR) > North Atlantic Oscillation (NAO) > Arctic Oscillation (AO). The indices’ impact was minimal in the winter precipitation. ENSO types’ correlations (Southern Oscillation Index-SOI and Niño 3.4) were moderate and significant at α = 0.05. Rainfall at most stations positively correlates with AO and EAWR in spring and autumn. During the study period, warm phases of ENSO (i.e., El Niño) intensified autumn precipitation. Simultaneously with warm phases of EAWR or AO, more influence on autumn precipitation is exerted. Cold phases of ENSO (i.e., La Niña) have an adverse impact compared to El Niño. EAWR co-variation was evident only with the ENSO. Regarding AO, a non-meaningful action was noticed during the neutral phases of ENSO and EAWR. The findings of this study help understand and predict the seasonal trend of precipitation over the Gaza region. This is essential to set up climate change mitigation and adaptation strategies in the EM region.

scholarly journals Hydrologic impacts on human health : El Niño Southern Oscillation and cholera

2020 ◽  
Author(s):  
Elissa Yeates ◽  
Kayla Cotterman ◽  
Angela Rhodes
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Climate Impact ◽  
Incidence Rates ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Enso Cycle ◽  
Hydrologic Impacts ◽  
The 1960S

A non-stationary climate imposes considerable challenges regarding potential public health concerns. The El Niño Southern Oscillation (ENSO) cycle, which occurs every 2 to 7 years, correlates positively with occurrences of the waterborne disease cholera. The warm sea surface temperatures and extreme weather associated with ENSO create optimal conditions for breeding the Vibrio cholerae pathogen and for human exposure to the pathogenic waters. This work explored the impacts of ENSO on cholera occurrence rates over the past 50 years by examining annual rates of suspected cholera cases per country in relation to ENSO Index values. This study provides a relationship indicating when hydrologic conditions are optimal for cholera growth, and presents a statistical approach to answer three questions: Are cholera outbreaks more likely to occur in an El Niño year? What other factors impact cholera outbreaks? How will the future climate impact cholera incidence rates as it relates to conditions found in ENSO? Cholera outbreaks from the 1960s to the present are examined focusing on regions of Central and South America, and southern Asia. By examining the predictive relationship between climate variability and cholera, we can draw conclusions about future vulnerability to cholera and other waterborne pathogenic diseases.

scholarly journals A first shallow firn-core record from Glaciar La Ollada, Cerro Mercedario, central Argentine Andes

2006 ◽  
Vol 43 ◽  
pp. 14-22 ◽  
Author(s):  
David Bolius ◽  
Margit Schwikowski ◽  
Theo Jenk ◽  
Heinz W. Gäggeler ◽  
Gino Casassa ◽  
...  
Keyword(s):  
El Niño ◽  
Southern Oscillation Index ◽  
El Nino ◽  
Southern Oscillation ◽  
Winter Precipitation ◽  
Time Span ◽  
Paleoclimate Reconstruction ◽  
Central Chile ◽  
Annual Layer ◽  
Firn Core

AbstractIn January 2003, shallow firn cores were recovered from Glaciar Esmeralda on Cerro del Plomo (33°14’S, 70°13’W; 5300 ma.s.l.), central Chile, and from Glaciar La Ollada on Cerro Mercedario (31°58’S, 70°07’W; 6070 ma.s.l.), Argentina, in order to find a suitable archive for paleoclimate reconstruction in a region strongly influenced by the El Nino-Southern Oscillation. In the area between 28°S and 35°S, the amount of winter precipitation is significantly correlated to the Southern Oscillation Index, with higher values during El Nino years. Glaciochemical analysis indicates that the paleo-record at Glaciar La Ollada is well preserved, whereas at Glaciar Esmeralda the record is strongly influenced by meltwater formation and percolation. A preliminary dating of the Mercedario core by annual-layer counting results in a time-span of 17 years (1986-2002), yielding an average annual net accumulation of 0.45 m w.e.

Response of benthic macroinvertebrate communities to El Niño related drought events in six upland streams in south-central Ontario

2008 ◽  
Vol 65 (5) ◽  
pp. 890-905 ◽  
Author(s):  
Beth Gilbert ◽  
Peter J Dillon ◽  
Keith M Somers ◽  
Ron A Reid ◽  
Lem Scott
Keyword(s):  
Relative Abundance ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Benthic Macroinvertebrate ◽  
Macroinvertebrate Communities ◽  
South Central ◽  
Effects Of Drought ◽  
One Year ◽  
The Impact

We examined the effects of extreme drought events on benthic macroinvertebrate (BMI) community structure in six forested upland streams in south-central Ontario, Canada, during a 9-year period. Variation in the mean winter El Niño – Southern Oscillation Index was strongly correlated with drought conditions (zero flow days) in the study streams. Drought onset and duration varied among study streams and among years. Below-average precipitation coincided with the occurrence of drought, although it remains unclear if snowfall and rainfall contributed equally to the impact of decreased precipitation. Increased relative abundance of Ephemeroptera, Plecoptera, and Trichoptera (EPT) one year following drought and decreased relative abundance two years after drought indicated high resistance but poor resilience. In contrast, chironomids showed poor resistance and high resilience. Although these patterns were not consistent across all streams, temporal coherence among streams was found in percent EPT, percent chironomids, and percent dipterans, suggesting that drought acts as a disturbance mechanism that simplifies benthos community assemblages. Biocriteria developed from 22 nearby reference streams indicated that abnormal BMI communities occurred only after recurring episodes of drought, indicating that the effects of drought are cumulative. Headwater streams may prove to be sentinel ecosystems for monitoring the impacts of climate change.

scholarly journals The Quasi-Biweekly Oscillation of Winter Precipitation Associated with ENSO over Southern China

Atmosphere ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 406 ◽  
Author(s):  
Qiaoyu Tong ◽  
Suxiang Yao
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern China ◽  
Low Pressure ◽  
Winter Precipitation ◽  
Precipitation Variability ◽  
Pressure System ◽  
Vorticity Advection ◽  
Low Pressure System ◽  
Low Pressure Systems

Using ERA-interim Reanalysis data and observational data, the intraseasonal oscillation of the winter rainfall in southern China is studied. The mean square deviation of daily precipitation is used to express precipitation variability, and winter precipitation variability over southern China is determined to be highly correlated with sea surface temperature (SST) in central and eastern tropical Pacific; the dominant period of the precipitation is 10–30 days, which reflects quasi-biweekly oscillation. Examination of 1000 hPa geopotential height suggests that key low-pressure systems affecting the intraseasonal precipitation come from Lake Baikal, but with different travel paths. In El Niño years, key low-pressure systems converge with other low-pressure systems and move southeastward until reaching South China, while in La Niña years, only one low-pressure system can reach southern China. Meanwhile, the explosive development of the low-pressure system is mainly caused by the joint effects of thermal advection and vorticity advection in El Niño, and only vorticity advection accounted for the dominant status in La Niña. Multiscale analysis shows that the meridional distribution of intraseasonal circulation plays an important role on the thermal transmission and brings strong warm advection from low latitudes to high latitudes in El Niño.

scholarly journals Effect of precipitation seasonality on annual oxygen isotopic composition in the area of spring persistent rain in southeastern China and its paleoclimatic implication

2020 ◽  
Vol 16 (1) ◽  
pp. 211-225 ◽  
Author(s):  
Haiwei Zhang ◽  
Hai Cheng ◽  
Yanjun Cai ◽  
Christoph Spötl ◽  
Ashish Sinha ◽  
...  
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Asian Summer Monsoon ◽  
Precipitation Amount ◽  
Annual Precipitation ◽  
Lower Amount ◽  
Seasonal Precipitation ◽  
Precipitation Seasonality ◽  
Precipitation Δ18o

Abstract. This study examines the seasonality of precipitation amount and δ18O over the monsoon region of China (MRC). We found that the precipitation amount associated with the East Asian summer monsoon (EASM) in the spring persistent rain (SPR) region is equivalent to that of the nonsummer monsoon (NSM). The latter contributes ∼50 % to amount-weighted annual δ18O values, in contrast with other areas in the MRC, where the δ18O of annual precipitation is dominated by EASM precipitation. Interannual relationships between the El Niño–Southern Oscillation (ENSO) index, simulated δ18O data from IsoGSM, and seasonal precipitation amount in the SPR region were also examined. We found that on interannual timescales, the seasonality of precipitation amount (EASM ∕ NSM ratio) was modulated by ENSO and primarily influences the variability of amount-weighted annual precipitation δ18O values in the SPR region, although integrated regional convection and moisture source and transport distance may also play subordinate roles. During El Niño (La Niña) phases, less (more) EASM and more (less) NSM precipitation leading to lower (higher) EASM ∕ NSM precipitation amount ratios results in higher (lower) amount-weighted annual precipitation δ18O values and, consequently, in higher (lower) speleothem δ18O values. Characterizing spatial differences in seasonal precipitation is, therefore, key to correctly interpreting speleothem δ18O records from the MRC.

scholarly journals Eastern Pacific ITCZ Dipole and ENSO Diversity

2018 ◽  
Vol 31 (11) ◽  
pp. 4449-4462 ◽  
Author(s):  
Shang-Ping Xie ◽  
Qihua Peng ◽  
Youichi Kamae ◽  
Xiao-Tong Zheng ◽  
Hiroki Tokinaga ◽  
...  
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Deep Convection ◽  
Relative Strength ◽  
Eastern Equatorial Pacific ◽  
Ocean Atmosphere ◽  
Preceding Season ◽  
Mean Climate ◽  
One Year

Abstract The eastern tropical Pacific features strong climatic asymmetry across the equator, with the intertropical convergence zone (ITCZ) displaced north of the equator most of time. In February–April (FMA), the seasonal warming in the Southern Hemisphere and cooling in the Northern Hemisphere weaken the climatic asymmetry, and a double ITCZ appears with a zonal rainband on either side of the equator. Results from an analysis of precipitation variability reveal that the relative strength between the northern and southern ITCZ varies from one year to another and this meridional seesaw results from ocean–atmosphere coupling. Surprisingly this meridional seesaw is triggered by an El Niño–Southern Oscillation (ENSO) of moderate amplitudes. Although ENSO is originally symmetric about the equator, the asymmetry in the mean climate in the preceding season introduces asymmetric perturbations, which are then preferentially amplified by coupled ocean–atmosphere feedback in FMA when deep convection is sensitive to small changes in cross-equatorial gradient of sea surface temperature. This study shows that moderate ENSO follows a distinct decay trajectory in FMA and southeasterly cross-equatorial wind anomalies cause moderate El Niño to dissipate rapidly as southeasterly cross-equatorial wind anomalies intensify ocean upwelling south of the equator. In contrast, extreme El Niño remains strong through FMA as enhanced deep convection causes westerly wind anomalies to intrude and suppress ocean upwelling in the eastern equatorial Pacific.

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