scholarly journals Climatology and Interannual Variability of Quasi-Global Intense Precipitation Using Satellite Observations

2016 ◽  
Vol 29 (15) ◽  
pp. 5447-5468 ◽  
Author(s):  
Martina Ricko ◽  
Robert F. Adler ◽  
George J. Huffman
Keyword(s):  
Daily Precipitation ◽  
Southern Oscillation ◽  
Regional Scale ◽  
Tropical Rainfall Measuring Mission ◽  
Spatial And Temporal Variation ◽  
Intense Rainfall ◽  
Precipitation Regime ◽  
Enso Events ◽  
Intense Precipitation ◽  
The One

Abstract Climatology and variations of recent mean and intense precipitation over a near-global (50°S–50°N) domain on a monthly and annual time scale are analyzed. Data used to derive daily precipitation to examine the effects of spatial and temporal coverage of intense precipitation are from the current Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) 3B42 version 7 precipitation product, with high spatial and temporal resolution during 1998–2013. Intense precipitation is defined by several different parameters, such as a 95th percentile threshold of daily precipitation, a mean precipitation that exceeds that percentile, or a fixed threshold of daily precipitation value (e.g., 25 and 50 mm day−1). All parameters are used to identify the main characteristics of spatial and temporal variation of intense precipitation. High correlations between examined parameters are observed, especially between climatological monthly mean precipitation and intense precipitation, over both tropical land and ocean. Among the various parameters examined, the one best characterizing intense rainfall is a fraction of daily precipitation ≥ 25 mm day−1, defined as a ratio between the intense precipitation above the used threshold and mean precipitation. Regions that experience an increase in mean precipitation likely experience a similar increase in intense precipitation, especially during the El Niño–Southern Oscillation (ENSO) events. Improved knowledge of this intense precipitation regime and its strong connection to mean precipitation given by the fraction parameter can be used for monitoring of intense rainfall and its intensity on a global to regional scale.

The dynamics and impacts of the December 2017 catastrophic mass flow Villa Santa Lucia, Chile

2020 ◽  
Author(s):  
Holly Chubb ◽  
Andrew Russell ◽  
Alejandro Dussaillant ◽  
Stuart Dunning
Keyword(s):  
Debris Flow ◽  
Mass Flow ◽  
Southern Oscillation ◽  
Significant Risk ◽  
Flow Path ◽  
Intense Rainfall ◽  
Enso Events ◽  
The Future ◽  
Mass Flows ◽  
Insight Into

<p>Landslides and mass flows are dynamic processes that involve the movement of rock, debris and earth down a slope. As a result of the 2017 catastrophic mass flow, these processes have been further established as a significant risk to the population of Chile, and further afield. Through field site investigations, it is possible to develop a greater insight into the mechanisms and conditions that influence the dynamics of these phenomena.</p><p>On Saturday 16 December 2017, a catastrophic debris flow (aluvión) partially destroyed the village of Villa Santa Lucía and a 5 km long reach of the Panamerican Highway resulting in 22 fatalities. The apparent trigger was an intense rainfall event of 124 mm in 24h associated with an elevated 0˚C isotherm (1600 m.a.s.l.) that led to the failure of 5.5 - 6.8x10<sup>6</sup>m<sup>3 </sup> mountainside in the uppermost catchment of Rio Burritos near the SE end of the Cordón Yelcho Glacier. The landslide transformed rapidly into a highly mobile debris flow as it entrained water from the Rio Burritos river and glacier ice from the Cordón Yelcho.</p><p>This study characterises the geomorphological impacts and dynamics of the 2017 mass flow. Post-event DEMs, aerial photos and satellite imagery provided the basis for geomorphological mapping and terrain analysis. Fieldwork in January 2019 allowed sampling of mass flow deposits, logging of sedimentary sections and dGPS surveys.</p><p>Both erosion and deposition occurred over the Villa Santa Lucía flow path. Erosion occurred more frequently in the first 7.9km of the flow path due to high slope angles and presence of the Rio Burritos that channelised flow. A high proportion of coarse particles in the flow enhanced basal scouring and erosion of the valley sides, resulting in significant flow bulking. A total of 7.6x10<sup>6</sup>m<sup>3</sup> – 7.7x10<sup>6</sup>m<sup>3 </sup> of material was deposited across the latter 6.3km of the flow path.</p><p>Sediment sample analysis showed that the flow began as cohesive and viscous in nature in spite of a lack of clay particles and high proportions of sands and gravels. The addition of water from the Rio Burritos reduced the viscosity of the flow as the flow propagated downstream. This resulted in enhanced lobe spreading and particle interactions in the depositional zone. In spite of this water entrainment, the flow remained both sediment and debris rich over its duration.</p><p>Catastrophic mass flows like the event at Villa Santa Lucía are likely to become more common around the world in the future as intense rainfall events become more frequent due to the dominance of El Nino Southern Oscillation (ENSO) events. By studying recent catastrophic mass flow events, an insight into the relationship between mass flow triggers and flow composition will be developed. This will allow for greater understanding of how these influence mass flow behaviours. As a result, it may then be possible to predict the rheology and routes of future flows. These predictions have the ability to be used to protect communities from such events in the future.</p>

scholarly journals Influence of three phases of El Niño–Southern Oscillation on daily precipitation regimes in China

2019 ◽  
Vol 23 (2) ◽  
pp. 883-896 ◽  
Author(s):  
Aifeng Lv ◽  
Bo Qu ◽  
Shaofeng Jia ◽  
Wenbin Zhu
Keyword(s):  
El Niño ◽  
Daily Precipitation ◽  
El Nino ◽  
Southern Oscillation ◽  
Annual Precipitation ◽  
Rainfall Events ◽  
Enso Events ◽  
Precipitation Regimes ◽  
Precipitation Anomalies ◽  
Three Phases

Abstract. In this study, the impacts of the El Niño–Southern Oscillation (ENSO) on daily precipitation regimes in China are examined using data from 713 meteorological stations from 1960 to 2013. We discuss the annual precipitation, frequency and intensity of rainfall events, and precipitation extremes for three phases (eastern Pacific El Niño – EP, Central Pacific El Niño – CP, and La Niña – LN) of ENSO events in both ENSO developing and ENSO decaying years. A Mann–Whitney U test was applied to assess the significance of precipitation anomalies due to ENSO. Results indicated that the three phases each had a different impact on daily precipitation in China and that the impacts in ENSO developing and decaying years were significantly different. EP phases caused less precipitation in developing years but more precipitation in decaying years; LN phases caused a reverse pattern. The precipitation anomalies during CP phases were significantly different than those during EP phases, and a clear pattern was found in decaying years across China, with positive anomalies over northern China and negative anomalies over southern China. Further analysis revealed that anomalies in frequency and intensity of rainfall accounted for these anomalies in annual precipitation; in EP developing years, negative anomalies in both frequency and intensity of rainfall events resulted in less annual precipitation, while in CP decaying years, negative anomalies in either frequency or intensity typically resulted in reduced annual precipitation. ENSO events tended to trigger extreme precipitation events. In EP and CP decaying years and in LN developing years, the number of very wet day precipitation (R95 p), the maximum rainfall in 1 day (Rx1d), and the number of consecutive wet days (CWD) all increased, suggesting an increased risk of flooding. On the other hand, more dry spells (DSs) occurred in EP developing years, suggesting an increased likelihood of droughts during this phase. Possible mechanisms responsible for these rainfall anomalies are speculated to be the summer monsoon and tropical cyclone anomalies in ENSO developing and decaying years.

scholarly journals Snow cover dynamics in Andean watersheds of Chile (32.0–39.5° S) during the years 2000–2016

2017 ◽  
Vol 21 (10) ◽  
pp. 5111-5126 ◽  
Author(s):  
Alejandra Stehr ◽  
Mauricio Aguayo
Keyword(s):  
Remote Sensing ◽  
Snow Cover ◽  
Southern Oscillation ◽  
Statistical Tests ◽  
Spatial And Temporal Variability ◽  
Economic Activities ◽  
Precipitation Regime ◽  
Snow Cover Area ◽  
Enso Events ◽  
Chilean Andes

Abstract. Andean watersheds present important snowfall accumulation mainly during the winter, which melts during the spring and part of the summer. The effect of snowmelt on the water balance can be critical to sustain agriculture activities, hydropower generation, urban water supplies and wildlife. In Chile, 25 % of the territory between the region of Valparaiso and Araucanía comprises areas where snow precipitation occurs. As in many other difficult-to-access regions of the world, there is a lack of hydrological data of the Chilean Andes related to discharge, snow courses, and snow depths, which complicates the analysis of important hydrological processes (e.g. water availability). Remote sensing provides a promising opportunity to enhance the assessment and monitoring of the spatial and temporal variability of snow characteristics, such as the snow cover area (SCA) and snow cover dynamic (SCD). With regards to the foregoing questions, the objective of the study is to evaluate the spatiotemporal dynamics of the SCA at five watersheds (Aconcagua, Rapel, Maule, Biobío and Toltén) located in the Chilean Andes, between latitude 32.0 and 39.5° S, and to analyse its relationship with the precipitation regime/pattern and El Niño–Southern Oscillation (ENSO) events. Those watersheds were chosen because of their importance in terms of their number of inhabitants, and economic activities depending on water resources. The SCA area was obtained from MOD10A2 for the period 2000–2016, and the SCD was analysed through a number of statistical tests to explore observed trends. In order to verify the SCA for trend analysis, a validation of the MOD10A2 product was done, consisting of the comparison of snow presence predicted by MODIS with ground observations. Results indicate that there is an overall agreement of 81 to 98 % between SCA determined from ground observations and MOD10A2, showing that the MODIS snow product can be taken as a feasible remote sensing tool for SCA estimation in southern–central Chile. Regarding SCD, no significant reduction in SCA for the period 2000–2016 was detected, with the exception of the Aconcagua and Rapel watersheds. In addition to that, an important decline in SCA in the five watersheds for the period of 2012 and 2016 was also evident, which is coincidental with the rainfall deficit for the same years. Findings were compared against ENSO episodes that occurred during 2010–2016, detecting that Niña years are coincident with maximum SCA during winter in all watersheds.

scholarly journals Evaluation of the Hydrological Cycle in the ECHAM5 Model

2006 ◽  
Vol 19 (16) ◽  
pp. 3810-3827 ◽  
Author(s):  
Stefan Hagemann ◽  
Klaus Arpe ◽  
Erich Roeckner
Keyword(s):  
General Circulation ◽  
Hydrological Cycle ◽  
Southern Oscillation ◽  
Regional Scale ◽  
Vertical Resolution ◽  
Model Simulations ◽  
Enso Events ◽  
Precipitation Response ◽  
Simulated Precipitation ◽  
The Impact

Abstract This study investigates the impact of model resolution on the hydrological cycle in a suite of model simulations using a new version of the Max Planck Institute for Meteorology atmospheric general circulation model (AGCM). Special attention is paid to the evaluation of precipitation on the regional scale by comparing model simulations with observational data in a number of catchments representing the major river systems on the earth in different climate zones. It is found that an increased vertical resolution, from 19 to 31 atmospheric layers, has a beneficial effect on simulated precipitation with respect to both the annual mean and the annual cycle. On the other hand, the influence of increased horizontal resolution, from T63 to T106, is comparatively small. Most of the improvements at higher vertical resolution, on the scale of a catchment, are due to large-scale moisture transport, whereas the impact of local water recycling through evapotranspiration is somewhat smaller. At high horizontal and vertical resolution (T106L31) the model captures most features of the observed hydrological cycle over land, and also the local and remote precipitation response to El Niño–Southern Oscillation (ENSO) events. Major deficiencies are the overestimation of precipitation over the oceans, especially at higher vertical resolution, along steep mountain slopes and during the Asian summer monsoon season, whereas a dry bias exists over Australia. In addition, the model fails to reproduce the observed precipitation response to ENSO variability in the Indian Ocean and Africa. This might be related to missing coupled air–sea feedbacks in an AGCM forced with observed sea surface temperatures.

scholarly journals Floods and droughts in association with cold and warm ENSO events and related circulation features

MAUSAM ◽  
2021 ◽  
Vol 50 (4) ◽  
pp. 355-364
Author(s):  
MEDHA KHOLE ◽  
U.S DE
Keyword(s):  
Summer Monsoon ◽  
Extreme Event ◽  
Southern Oscillation ◽  
Indian Subcontinent ◽  
Phase Locking ◽  
Regional Scale ◽  
Circulation Pattern ◽  
Enso Events ◽  
Monsoon System ◽  
Floods And Droughts

For the Indian subcontinent. the occurrence of floods and droughts is closely linked with the summer monsoon activity. The phenomenon of El Nino-Southern Oscillation (ENSO) has been established to be one of the major teleconnections of Indian Summer Monsoon. Also the relationship between the circulation features and summer monsoon activity is well documented in the literature. The interaction of F.NSO with monsoon system was known to the seasonal forecasters in India from the days of G. Walker. Northland (1953) summarising these results has remarked that ‘Monsoon has a prolonged influence on the global weather rather than global weather parameters influencing the monsoon’. 1990-94 was a prolonged period of warm ENSO producing weather anomalies in different regions of the globe. Yet during the same period all India rainfall was very close to normal and in fact. 1994 was a year of abundant rainfall for India. The aim of the study is to examine some of these features more critically.   It is observed that ENSO has a modifying effect on the regional scale circulation pattern and possible interactions and/or phase-Locking with the planetary scale circulation pattern. which results into the occurrence or non-occurrence of an extreme event. Also, a qualitative analysis is carried for a period 1960-90 to assess how far the mid-season rainfall deficiency is made up at the end of the season. It is observed that even during drought years, the mid-season rainfall deficiency is made up at the end of the season for a considerable percentage of the total number of cases.

scholarly journals Prediction of September–December Fire in New Caledonia (Southwestern Pacific) Using July Niño-4 Sea Surface Temperature Index

2013 ◽  
Vol 52 (3) ◽  
pp. 623-633 ◽  
Author(s):  
Vincent Moron ◽  
Renaud Barbero ◽  
Morgan Mangeas ◽  
Laurent Borgniet ◽  
Thomas Curt ◽  
...  
Keyword(s):  
New Caledonia ◽  
Southern Oscillation ◽  
Regional Scale ◽  
Sea Surface ◽  
Small Scale ◽  
Central Pacific ◽  
Climatic Forcing ◽  
Austral Spring ◽  
Burned Areas ◽  
Enso Events

AbstractAn empirical statistical scheme for predicting September–December fires in New Caledonia in the southwestern Pacific Ocean region using a cross-validated generalized linear model has been developed for the 2000–10 period. The predictor employs July sea surface temperatures (SST) recorded over the Niño-4 box (5°S–5°N, 160°–210°E), which are closely related to austral spring (September–November) rainfall anomalies across New Caledonia. The correlation between the logarithm of observed and simulated total burned areas across New Caledonia is 0.87. A decrease in the local-scale skill (median correlation between the log of observed and simulated total burned areas in a 20-km radius around a rain gauge = 0.46) around the main town (Nouméa) and its suburbs in the southwest of Grande Terre, and also in northern New Caledonia, could be associated either with a weaker climatic forcing from the Niño-4 SST index or a small-scale climatic forcing not linearly related to the El Niño–Southern Oscillation (ENSO) phenomenon. It is more likely that the decrease is tied to the influence of human-driven factors that blur the regional-scale climatic signal mostly associated with central Pacific ENSO events.

scholarly journals The Influence of ENSO and MJO on Drought in Different Ecological Geographic Regions in China

2021 ◽  
Vol 13 (5) ◽  
pp. 875
Author(s):  
Lei Zhou ◽  
Siyu Wang ◽  
Mingyi Du ◽  
Qiang Chen ◽  
Congcong He ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Spatial Correlation ◽  
Southern Oscillation ◽  
Regional Scale ◽  
Meteorological Drought ◽  
Agricultural Drought ◽  
Tibet Plateau ◽  
Enso Events ◽  
Geographical Regions ◽  
The Impact

Mastering the spatial and temporal differences of ENSO (EI Niño-Southern Oscillation) and MJO (Madden–Julian Oscillation) and their influence on drought is very important for accurately monitoring and forecasting drought. In this study, spatiotemporal characteristics and variability of the impact of ENSO and MJO on drought were analyzed from the perspectives of meteorological drought and agricultural drought through temporal and spatial correlation analyses of China’s 48 eco-geographical regions. The results show a strong correlation between drought and ENSO and MJO in general. The spatial correlation coefficients are different, and the response of extreme events varies in different regions. The influence of ENSO and MJO on agricultural drought is higher than that on meteorological drought. ENSO and MJO have a considerable influence on agricultural drought in regions such as the Qinghai-Tibet Plateau and Xinjiang, with the highest correlation coefficient of 0.72. A significant influence of ENSO and MJO on meteorological drought was found in the Jiangnan region with the highest correlation coefficient of 0.40. In addition, agricultural drought shows a significant time lag in response to ENSO events. When the lag time is six months, the time series presents the highest correlation coefficient with the mean value of the correlation coefficient reaching 0.38 and the maximum value reaching 0.75. This research is of great significance for understanding the spatiotemporal correlation between climate patterns and drought on a large regional scale and it provides further insights into the teleconnection mechanisms of drought.

scholarly journals Interannual variability of the frequency of MJO phases and its association with two types of ENSO

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Panini Dasgupta ◽  
M. K. Roxy ◽  
Rajib Chattopadhyay ◽  
C. V. Naidu ◽  
Abirlal Metya
Keyword(s):  
Indian Ocean ◽  
Interannual Variability ◽  
Southern Oscillation ◽  
Regional Scale ◽  
Moisture Distribution ◽  
Eastern Pacific ◽  
Central Pacific ◽  
Frequency Pattern ◽  
Enso Events ◽  
Enso Phases

AbstractIn this study, we reexamine the effect of two types of El Niño Southern Oscillation (ENSO) modes on Madden Julian Oscillation (MJO) activity in terms of the frequency of MJO phases. Evaluating all-season data, we identify two dominant zonal patterns of MJO frequency exhibiting prominent interannual variability. These patterns are structurally similar to the Wheeler and Hendon (Mon. Weather Rev. 132:1917–1932, 2004) RMM1 and RMM2 spatial patterns. The first pattern explains a higher frequency of MJO activity over the Maritime Continent and a lower frequency over the central Pacific Ocean and the western Indian Ocean, or vice versa. The second pattern is associated with a higher frequency of MJO active days over the eastern Indian Ocean and a lower frequency over the western Pacific, or vice versa. We find that these two types of MJO frequency patterns are related to the central Pacific and eastern Pacific ENSO modes. From the positive to the negative ENSO (central Pacific or eastern Pacific) phases, the respective MJO frequency patterns change their sign. The MJO frequency patterns are the lag response of the underlying ocean state. The coupling between ocean and atmosphere is exceedingly complex. The first MJO frequency pattern is most prominent during the negative central-Pacific (CP-type) ENSO phases (specifically during September–November and December-February seasons). The second MJO frequency pattern is most evident during the positive eastern-Pacific (EP-type) ENSO phases (specifically during March–May, June–August and September–November). Different zonal circulation patterns during CP-type and EP-type ENSO phases alter the mean moisture distribution throughout the tropics. The horizontal convergence of mean background moisture through intraseasonal winds are responsible for the MJO frequency anomalies during the two types of ENSO phases. The results here show how the MJO activity gets modulated on a regional scale in the presence of two types of ENSO events and can be useful in anticipating the seasonal MJO conditions from a predicted ENSO state.

scholarly journals Modelling the frequency distribution of inter-arrival times from daily precipitation time-series in North-West Italy

2018 ◽  
Vol 50 (1) ◽  
pp. 339-357 ◽  
Author(s):  
Giorgio Baiamonte ◽  
Luca Mercalli ◽  
Daniele Cat Berro ◽  
Carmelo Agnese ◽  
Stefano Ferraris
Keyword(s):  
Time Series ◽  
Frequency Distribution ◽  
Daily Precipitation ◽  
Regional Scale ◽  
Precipitation Time Series ◽  
Precipitation Regime ◽  
Arrival Times ◽  
North West ◽  
Pettitt Test ◽  
Precipitation Regimes

Abstract The discrete three-parameter Lerch distribution is used to analyse the frequency distribution of inter-arrival times derived from 26 daily precipitation time-series, collected by stations located throughout a 28,000 km2 area in North-West Italy (altitudes ranging from 113 m to 2,170 m a.s.l.). The precipitation regime of these Alpine regions is very different (latitude 44.5 to 46.5 N) from the typical Mediterranean precipitation regime of the island of Sicily (latitude 37 to 38 N), where the Lerch distribution has already been tested and whose results are compared. In order to verify the homogeneity of the precipitation time series, the Pettitt test was preliminarily performed. In this work, a good fitting of the Lerch distribution to NW Italy is shown, thus evidencing the wide applicability of this kind of distribution, also allowing to jointly model dry spells and wet spells. The three parameters of the Lerch distribution showed rather different values than the Sicily ones, likely due to the very different precipitation regimes. Finally, a relevant spatial variability of inter-arrival times in the study area was revealed from the regional scale application of the probability distribution here described. The outcomes of this study could be of interest in different hydrologic applications.

scholarly journals Influence of three phases of El Niño-Southern Oscillation on daily precipitation regimes in China

2018 ◽  
Author(s):  
Aifeng Lv ◽  
Bo Qu ◽  
Shaofeng Jia ◽  
Wenbin Zhu
Keyword(s):  
El Niño ◽  
Daily Precipitation ◽  
El Nino ◽  
Southern Oscillation ◽  
Annual Precipitation ◽  
Rainfall Events ◽  
Enso Events ◽  
Precipitation Regimes ◽  
Precipitation Anomalies ◽  
Three Phases

Abstract. In this study, the impacts of the El Niño-Southern Oscillation (ENSO) on daily precipitation regimes in China are examined using data from 713 meteorological stations from 1960 to 2013. We discuss the annual precipitation, frequency and intensity of rainfall events, and precipitation extremes for three phases (Eastern Pacific El Niño (EP), Central Pacific El Niño (CP), and La Niña (LN)) of ENSO events in both ENSO developing and ENSO decaying years. A Mann–Whitney U test was applied to assess the significance of precipitation anomalies due to ENSO. Results indicated that the three phases each had a different impact on daily precipitation in China and that the impacts in ENSO developing and decaying years were significantly different. EP phases caused less precipitation in developing years but more precipitation in decaying years; LN phases caused a reverse pattern. The precipitation anomalies during CP phases were significantly different than those during EP phases and a clear pattern was found in decaying years across China, with positive anomalies over northern China and negative anomalies over southern China. ENSO events which altered the frequency and intensity of rainfall roughly paralleled anomalies in annual precipitation; in EP developing years, negative anomalies in both frequency and intensity of rainfall events resulted in less annual precipitation while in CP decaying years, negative anomalies in either frequency or intensity typically resulted in reduced annual precipitation. ENSO events triggered more extreme precipitation events. In EP and CP decaying years and in LN developing years, the number of very wet days (R95p), the maximum rainfall in one day (Rx1d), and the number of consecutive wet days (CWD) all increased, suggesting an increased risk of flooding. In addition, more dry spells (DS) occurred in EP developing years, suggesting an increased likelihood of droughts during this phase.

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