scholarly journals Spatiotemporal pattern variations of daily precipitation concentration and their relationship with possible causes in the Yangtze River Delta, China

2021 ◽  
Author(s):  
Chao Mei ◽  
Jiahong Liu ◽  
Ze Huang ◽  
Hao Wang ◽  
Kaibo Wang ◽  
...  
Keyword(s):  
El Niño ◽  
Arctic Oscillation ◽  
Daily Precipitation ◽  
El Nino ◽  
Yangtze River Delta ◽  
Spatiotemporal Pattern ◽  
Antarctic Oscillation ◽  
Precipitation Concentration Index ◽  
Precipitation Concentration ◽  
The Yangtze River Delta

Abstract Understanding the spatiotemporal pattern of precipitation concentration is important in the water cycle under changing environments. In this study, the daily precipitation concentration index in the Yangtze River Delta in China is calculated based on the Lorenz curves obtained from the observed data of 36 meteorological stations from 1960 to 2017, and spatiotemporal pattern variations and their possible causes are investigated. The driving forces of elevation, SUNSPOT, El Niño-Antarctic Oscillation, Pacific Decade Oscillation, and Arctic Oscillation are detected with correlation and wavelet analysis. Results show that, the daily precipitation concentration index ranges from 0.55 to 0.62 during the study period, 22 of 36 stations (accounting for 61%) show increasing trends, while three stations increase significantly at the 95% significant level. Relationship analysis indicates that the daily precipitation concentration shows a slightly negative correlation with elevation, while the relationships with SUNSPOT, El Niño-Antarctic Oscillation, Pacific Decade Oscillation, and Arctic Oscillation are complicated and diverse, there are different correlations and significance levels in different years. Further analysis shows that SUNSPOT is significantly correlated with El Niño-Antarctic Oscillation, Pacific Decade Oscillation, and Arctic Oscillation, which suggests that SUNSPOT may be an important factor that drives the changes of the three large-scale atmosphere circulation factors and causes precipitation concentration changing indirectly. These results provide further understandings of precipitation variations, which are meaningful for regional flood risk management under climate change.

Changes in Observed Daily Precipitation over the United States between 1950–79 and 1980–2009

2013 ◽  
Vol 14 (1) ◽  
pp. 105-121 ◽  
Author(s):  
R. W. Higgins ◽  
V. E. Kousky
Keyword(s):  
United States ◽  
Great Plains ◽  
El Niño ◽  
Daily Precipitation ◽  
El Nino ◽  
Southern Oscillation ◽  
Heavy Precipitation ◽  
The United States ◽  
Enso Cycle ◽  
Precipitation Events

Abstract Changes in observed daily precipitation over the conterminous United States between two 30-yr periods (1950–79 and 1980–2009) are examined using a 60-yr daily precipitation analysis obtained from the Climate Prediction Center (CPC) Unified Raingauge Database. Several simple measures are used to characterize the changes, including mean, frequency, intensity, and return period. Seasonality is accounted for by examining each measure for four nonoverlapping seasons. The possible role of the El Niño–Southern Oscillation (ENSO) cycle as an explanation for differences between the two periods is also examined. There have been more light (1 mm ≤ P < 10 mm), moderate (10 mm ≤ P < 25 mm), and heavy (P ≥ 25 mm) daily precipitation events (P) in many regions of the country during the more recent 30-yr period with some of the largest and most spatially coherent increases over the Great Plains and lower Mississippi Valley during autumn and winter. Some regions, such as portions of the Southeast and the Pacific Northwest, have seen decreases, especially during the winter. Increases in multiday heavy precipitation events have been observed in the more recent period, especially over portions of the Great Plains, Great Lakes, and Northeast. These changes are associated with changes in the mean and frequency of daily precipitation during the more recent 30-yr period. Difference patterns are strongly related to the ENSO cycle and are consistent with the stronger El Niño events during the more recent 30-yr period. Return periods for both heavy and light daily precipitation events during 1950–79 are shorter during 1980–2009 at most locations, with some notable regional exceptions.

scholarly journals Precipitation Extremes Estimated by GPCP and TRMM: ENSO Relationships

2007 ◽  
Vol 8 (4) ◽  
pp. 678-689 ◽  
Author(s):  
Scott Curtis ◽  
Ahmed Salahuddin ◽  
Robert F. Adler ◽  
George J. Huffman ◽  
Guojun Gu ◽  
...  
Keyword(s):  
El Niño ◽  
Extreme Precipitation ◽  
Daily Precipitation ◽  
El Nino ◽  
Southern Oscillation ◽  
Global Precipitation Climatology Project ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Precipitation Frequency ◽  
Rain Rates

Abstract Global monthly and daily precipitation extremes are examined in relation to the El Niño–Southern Oscillation phenomenon. For each month around the annual cycle and in each 2.5° grid block, extremes in the Global Precipitation Climatology Project dataset are defined as the top five (wet) and bottom five (dry) mean rain rates from 1979 to 2004. Over the tropical oceans El Niño–Southern Oscillation events result in a spatial redistribution and overall increase in extremes. Restricting the analysis to land shows that El Niño is associated with an increase in frequency of dry extremes and a decrease in wet extremes resulting in no change in net extreme months. During La Niña an increase in frequency of dry extremes and no change in wet extremes are observed. Thus, because of the juxtaposition of tropical land areas with the ascending branches of the global Walker Circulation, El Niño (La Niña) contributes to generally dry (wet) conditions in these land areas. In addition, daily rain rates computed from the Tropical Rainfall Measuring Mission Multisatellite Precipitation Analysis are used to define extreme precipitation frequency locally as the number of days within a given season that exceeded the 95th percentile of daily rainfall for all seasons (1998–2005). During this period, the significant relationships between extreme daily precipitation frequency and Niño-3.4 in the Tropics are spatially similar to the significant relationships between seasonal mean rainfall and Niño-3.4. However, to address the shortness of the record extreme daily precipitation frequency is also related to seasonal rainfall for the purpose of identifying regions where positive seasonal rainfall anomalies can be used as proxies for extreme events. Finally, the longer (1979–2005) but coarser Global Precipitation Climatology Project analysis is reexamined to pinpoint regions likely to experience an increase in extreme precipitation during El Niño–Southern Oscillation events. Given the significance of El Niño–Southern Oscillation predictions, this information will enable the efficient use of resources in preparing for and mitigating the adverse effects of extreme precipitation.

The Diurnal Cycle of Precipitation in the Tropical Andes of Colombia

2005 ◽  
Vol 133 (1) ◽  
pp. 228-240 ◽  
Author(s):  
Germán Poveda ◽  
Oscar J. Mesa ◽  
Luis F. Salazar ◽  
Paola A. Arias ◽  
Hernán A. Moreno ◽  
...  
Keyword(s):  
Diurnal Cycle ◽  
El Niño ◽  
Daily Precipitation ◽  
El Nino ◽  
Madden Julian Oscillation ◽  
Tropical Andes ◽  
Rain Gauges ◽  
Easterly Wave ◽  
La Nina ◽  
Diurnal Cycle Of Precipitation

Abstract Using hourly records from 51 rain gauges, spanning between 22 and 28 yr, the authors study the diurnal cycle of precipitation over the tropical Andes of Colombia. Analyses are developed for the seasonal march of the diurnal cycle and its interannual variability during the two phases of El Niño–Southern Oscillation (ENSO). Also, the diurnal cycle is analyzed at intra-annual time scales, associated with the westerly and easterly phases of the Madden–Julian oscillation, as well as higher-frequency variability (<10 days), mainly associated with tropical easterly wave activity during ENSO contrasting years. Five major general patterns are identified: (i) precipitation exhibits clear-cut diurnal (24 h) and semidiurnal (12 h) cycles; (ii) the minimum of daily precipitation is found during the morning hours (0900–1100 LST) regardless of season or location; (iii) a predominant afternoon peak is found over northeastern and western Colombia; (iv) over the western flank of the central Andes, precipitation maxima occur either near midnight, or during the afternoon, or both; and (v) a maximum of precipitation prevails near midnight amongst stations located on the eastern flank of the central Cordillera. The timing of diurnal maxima is highly variable in space for a fixed time, although a few coherent regions are found in small groups of rain gauges within the Cauca and Magdalena River valleys. Overall, the identified strong seasonal variability in the timing of rainfall maxima appears to exhibit no relationship with elevation on the Andes. The effects of both phases of ENSO are highly consistent spatially, as the amplitude of hourly and daily precipitation diminishes (increases) during El Niño (La Niña), but the phase remains unaltered for the entire dataset. We also found a generalized increase (decrease) in hourly and daily rainfall rates during the westerly (easterly) phase of the Madden–Julian oscillation, and a diminished (increased) high-frequency activity in July–October and February–April during El Niño (La Niña) years, associated, among others, with lower (higher) tropical easterly wave (4–6 day) activity over the Caribbean.

scholarly journals State of the Climate in 2010

2011 ◽  
Vol 92 (6) ◽  
pp. S1-S236 ◽  
Author(s):  
J. Blunden ◽  
D. S. Arndt ◽  
M. O. Baringer
Keyword(s):  
Carbon Dioxide ◽  
Sea Ice ◽  
North Atlantic ◽  
El Niño ◽  
Arctic Oscillation ◽  
El Nino ◽  
La Niña ◽  
The Arctic ◽  
La Nina ◽  
The Antarctic

Several large-scale climate patterns influenced climate conditions and weather patterns across the globe during 2010. The transition from a warm El Niño phase at the beginning of the year to a cool La Niña phase by July contributed to many notable events, ranging from record wetness across much of Australia to historically low Eastern Pacific basin and near-record high North Atlantic basin hurricane activity. The remaining five main hurricane basins experienced below- to well-below-normal tropical cyclone activity. The negative phase of the Arctic Oscillation was a major driver of Northern Hemisphere temperature patterns during 2009/10 winter and again in late 2010. It contributed to record snowfall and unusually low temperatures over much of northern Eurasia and parts of the United States, while bringing above-normal temperatures to the high northern latitudes. The February Arctic Oscillation Index value was the most negative since records began in 1950. The 2010 average global land and ocean surface temperature was among the two warmest years on record. The Arctic continued to warm at about twice the rate of lower latitudes. The eastern and tropical Pacific Ocean cooled about 1°C from 2009 to 2010, reflecting the transition from the 2009/10 El Niño to the 2010/11 La Niña. Ocean heat fluxes contributed to warm sea surface temperature anomalies in the North Atlantic and the tropical Indian and western Pacific Oceans. Global integrals of upper ocean heat content for the past several years have reached values consistently higher than for all prior times in the record, demonstrating the dominant role of the ocean in the Earth's energy budget. Deep and abyssal waters of Antarctic origin have also trended warmer on average since the early 1990s. Lower tropospheric temperatures typically lag ENSO surface fluctuations by two to four months, thus the 2010 temperature was dominated by the warm phase El Niño conditions that occurred during the latter half of 2009 and early 2010 and was second warmest on record. The stratosphere continued to be anomalously cool. Annual global precipitation over land areas was about five percent above normal. Precipitation over the ocean was drier than normal after a wet year in 2009. Overall, saltier (higher evaporation) regions of the ocean surface continue to be anomalously salty, and fresher (higher precipitation) regions continue to be anomalously fresh. This salinity pattern, which has held since at least 2004, suggests an increase in the hydrological cycle. Sea ice conditions in the Arctic were significantly different than those in the Antarctic during the year. The annual minimum ice extent in the Arctic—reached in September—was the third lowest on record since 1979. In the Antarctic, zonally averaged sea ice extent reached an all-time record maximum from mid-June through late August and again from mid-November through early December. Corresponding record positive Southern Hemisphere Annular Mode Indices influenced the Antarctic sea ice extents. Greenland glaciers lost more mass than any other year in the decade-long record. The Greenland Ice Sheet lost a record amount of mass, as the melt rate was the highest since at least 1958, and the area and duration of the melting was greater than any year since at least 1978. High summer air temperatures and a longer melt season also caused a continued increase in the rate of ice mass loss from small glaciers and ice caps in the Canadian Arctic. Coastal sites in Alaska show continuous permafrost warming and sites in Alaska, Canada, and Russia indicate more significant warming in relatively cold permafrost than in warm permafrost in the same geographical area. With regional differences, permafrost temperatures are now up to 2°C warmer than they were 20 to 30 years ago. Preliminary data indicate there is a high probability that 2010 will be the 20th consecutive year that alpine glaciers have lost mass. Atmospheric greenhouse gas concentrations continued to rise and ozone depleting substances continued to decrease. Carbon dioxide increased by 2.60 ppm in 2010, a rate above both the 2009 and the 1980–2010 average rates. The global ocean carbon dioxide uptake for the 2009 transition period from La Niña to El Niño conditions, the most recent period for which analyzed data are available, is estimated to be similar to the long-term average. The 2010 Antarctic ozone hole was among the lowest 20% compared with other years since 1990, a result of warmer-than-average temperatures in the Antarctic stratosphere during austral winter between mid-July and early September.

Opposite Phases of the Antarctic Oscillation and Relationships with Intraseasonal to Interannual Activity in the Tropics during the Austral Summer

2005 ◽  
Vol 18 (5) ◽  
pp. 702-718 ◽  
Author(s):  
Leila M. V. Carvalho ◽  
Charles Jones ◽  
Tércio Ambrizzi
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Deep Convection ◽  
Low Frequency ◽  
Austral Summer ◽  
Longwave Radiation ◽  
Antarctic Oscillation ◽  
The Tropics ◽  
The Antarctic

Abstract The Antarctic Oscillation (AAO) has been observed as a deep oscillation in the mid- and high southern latitudes. In the present study, the AAO pattern is defined as the leading mode of the empirical orthogonal function (EOF-1) obtained from daily 700-hPa geopotential height anomalies from 1979 to 2000. Here the objective is to identify daily positive and negative AAO phases and relationships with intraseasonal activity in the Tropics and phases of the El Niño–Southern Oscillation (ENSO) during the austral summer [December–January–February (DJF)]. Positive and negative AAO phases are defined when the daily EOF-1 time coefficient is above (or below) one standard deviation of the DJF mean. Composites of low-frequency sea surface temperature variation, 200-hPa zonal wind, and outgoing longwave radiation (OLR) indicate that negative (positive) phases of the AAO are dominant when patterns of SST, convection, and circulation anomalies resemble El Niño (La Niña) phases of ENSO. Enhanced intraseasonal activity from the Tropics to the extratropics of the Southern (Northern) Hemisphere is associated with negative (positive) phases of the AAO. In addition, there is indication that the onset of negative phases of the AAO is related to the propagation of the Madden–Julian oscillation (MJO). Suppression of intraseasonal convective activity over Indonesia is observed in positive AAO phases. It is hypothesized that deep convection in the central tropical Pacific, which is related to either El Niño or eastward-propagating MJO, or a combination of both phenomena, modulates the Southern Hemisphere circulation and favors negative AAO phases during DJF. The alternation of AAO phases seems to be linked to the latitudinal migration of the subtropical upper-level jet and variations in the intensity of the polar jet. This, in turn, affects extratropical cyclone properties, such as origin, minimum/maximum central pressure, and their equatorward propagation.

scholarly journals Spatial distribution of the daily precipitation concentration index in Algeria

2015 ◽  
Vol 15 (3) ◽  
pp. 617-625 ◽  
Author(s):  
A. Benhamrouche ◽  
D. Boucherf ◽  
R. Hamadache ◽  
L. Bendahmane ◽  
J. Martin-Vide ◽  
...  
Keyword(s):  
Concentration Index ◽  
Rainfall Intensity ◽  
Daily Precipitation ◽  
Temporal Distribution ◽  
Daily Rainfall ◽  
Precipitation Concentration Index ◽  
Precipitation Concentration ◽  
Northern Country ◽  
Torrential Rainfall ◽  
Erosive Capacity

Abstract. In this paper, the spatial and temporal distribution of the daily precipitation concentration index (CI) in Algeria (south Mediterranean Sea) has been assessed. CI is an index related to the rainfall intensity and erosive capacity; therefore, this index is of great interest for studies on torrential rainfall and floods. Forty-two daily rainfall series based on high-quality and fairly regular rainfall records for the period from 1970 to 2008 were used. The daily precipitation CI results allowed the identification of three climate zones: the northern country, characterized by coastal regions with CI values between 0.59 and 0.63; the highlands, with values between 0.57 and 0.62, except for the region of Biskra (CI = 0.70); and the southern region of the country, with high rainfall concentrations with values between 0.62 and 0.69.

scholarly journals Association between stroke occurrence and changes in atmospheric circulation

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jone Vencloviene ◽  
Ricardas Radisauskas ◽  
Daina Kranciukaite-Butylkiniene ◽  
Abdonas Tamosiunas ◽  
Vidmantas Vaiciulis ◽  
...  
Keyword(s):  
North Atlantic Oscillation ◽  
Atmospheric Circulation ◽  
North Atlantic ◽  
El Niño ◽  
Arctic Oscillation ◽  
El Nino ◽  
Teleconnection Pattern ◽  
East Atlantic ◽  
Negatively Associated ◽  
The Impact

Abstract Background The impact of weather on morbidity from stroke has been analysed in previous studies. As the risk of stroke was mostly associated with changing weather, the changes in the daily stroke occurrence may be associated with changes in atmospheric circulation. The aim of our study was to detect and evaluate the association between daily numbers of ischaemic strokes (ISs) and haemorrhagic strokes (HSs) and the teleconnection pattern. Methods The study was performed in Kaunas, Lithuania, from 2000 to 2010. The daily numbers of ISs, subarachnoid haemorrhages (SAHs), and intracerebral haemorrhages (ICHs) were obtained from the Kaunas Stroke Register. We evaluated the association between these types of stroke and the teleconnection pattern by applying Poisson regression and adjusting for the linear trend, month, and other weather variables. Results During the study period, we analysed 4038 cases (2226 men and 1812 women) of stroke. Of these, 3245 (80.4%) cases were ISs, 533 (13.2%) cases were ICHs, and 260 (6.4%) cases were SAHs. An increased risk of SAH was associated with a change in mean daily atmospheric pressure over 3.9 hPa (RR = 1.49, 95% CI 1.14–1.96), and a stronger El Niño event had a protective effect against SAHs (RR = 0.34, 95% CI 0.16–0.69). The risk of HS was positively associated with East Atlantic/West Russia indices (RR = 1.13, 95% CI 1.04–1.23). The risk of IS was negatively associated with the Arctic Oscillation index on the same day and on the previous day (RR = 0.97, p < 0.033). During November–March, the risk of HS was associated with a positive North Atlantic Oscillation (NAO) (RR = 1.29, 95% CI 1.03–1.62), and the risk of IS was negatively associated with the NAO index (RR = 0.92, 95% CI 0.85–0.99). Conclusions The results of our study provide new evidence that the North Atlantic Oscillation, Arctic Oscillation, East Atlantic/West Russia, and El Niño-Southern Oscillation pattern may affect the risk of stroke. The impact of these teleconnections is not identical for various types of stroke. Emergency services should be aware that specific weather conditions are more likely to prompt calls for more severe strokes.

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