scholarly journals Drivers of past and predicted changes of rainfall in and around Mainland Southeast Asia

2021 ◽  
Author(s):  
Nikolaos Skliris ◽  
Robert Marsh ◽  
Ivan D. Haigh ◽  
Melissa Wood ◽  
Joel Hirschi ◽  
...  
Keyword(s):  
Southeast Asia ◽  
Extreme Precipitation ◽  
Hydrological Cycle ◽  
Rain Gauge ◽  
Northwestern Part ◽  
Precipitation Trend ◽  
Extreme Precipitation Events ◽  
Increasing Precipitation ◽  
Mainland Southeast Asia

Abstract Observational rain gauge/satellite and reanalysis datasets since the 1950s are evaluated for trends in mean and extreme rainfall over Mainland Southeast Asia (MSEA). Rain gauge data indicate strong increases exceeding 50% in both annual mean precipitation and various extreme precipitation indices over Vietnam and the northwestern part of the peninsula since 1979. A high degree of uncertainty is evident between reanalysis products in capturing long-term trends in continental precipitation. Evaporation increases over adjacent seas - the Arabian Sea, the Bay of Bengal, and the South China Sea in particular- may partially explain increasing precipitation in large parts of MSEA over the last 40 years. The remote influence of ENSO may also partially explain the recent precipitation trend towards a more intense regional hydrological cycle, in response to predominant La Niña states over recent decades. Increasing precipitation in MSEA is also associated with increased monsoon intensity in southeast Asia and a northward shift of the monsoon activity centre towards MSEA over 1979–2018. Long-term amplification of the regional hydrological cycle is further investigated, through analysis of CMIP5 coupled climate models in historical and RCP4.5/8.5 21st century scenario simulations. The CMIP5 ensemble mean shows robust wide-spread trends in wet season precipitation over the MSEA in both RCP scenarios linked with strong increases in evaporation in all major oceanic moisture sources. Results clearly demonstrate an intensification of the regional water cycle with increasing frequency and intensity of extreme precipitation events.

Trends in mean and extreme rainfall over Mainland Southeast Asia associated with warming-driven trends in evaporation 

2021 ◽  
Author(s):  
Nikolaos Skliris ◽  
Robert Marsh ◽  
Ivan Haigh ◽  
Melissa Wood ◽  
Joel Hirschi ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Southeast Asia ◽  
Extreme Precipitation ◽  
Northwestern Part ◽  
Indian Ocean Basin Mode ◽  
Moisture Sources ◽  
Extreme Precipitation Events ◽  
The Indian Ocean ◽  
Increasing Precipitation ◽  
Mainland Southeast Asia

<p>Rain-gauge datasets indicate strong increases in both annual mean and extreme precipitation over large parts of the Mainland Southeast Asia (MSEA) including Vietnam and the northwestern part of the peninsula over the last 40 years. Increasing precipitation is associated with increased monsoon intensity in southeast Asia and a northward shift of the monsoon activity centre towards MSEA. Warming-driven evaporation increases over the three main oceanic moisture sources - the Arabian Sea, the Bay of Bengal, and the South China Sea- may partially explain increasing precipitation in large parts of MSEA. Changes in the patterns of the two main modes of natural variability in the tropical Indian Ocean – the Indian Ocean Basin Mode (IOBM) and the Indian Ocean Dipole (IOD) – contribute to surface warming in these oceanic moisture source regions supplying precipitation to MSEA. Climate model projections show robust wide-spread trends in wet season precipitation with increasing frequency and intensity of extreme precipitation events throughout MSEA over the 21<sup>st</sup> century. Similar to observations, the projected precipitation trends are associated with strong warming-driven increases in evaporation in all major oceanic moisture sources supplying precipitation to MSEA.</p>

The effect of climate change on urban drainage: an evaluation based on regional climate model simulations

2006 ◽  
Vol 54 (6-7) ◽  
pp. 9-15 ◽  
Author(s):  
M. Grum ◽  
A.T. Jørgensen ◽  
R.M. Johansen ◽  
J.J. Linde
Keyword(s):  
Climate Change ◽  
Extreme Precipitation ◽  
Climate Model ◽  
Regional Climate ◽  
Rain Gauge ◽  
Urban Drainage ◽  
Extreme Precipitation Events ◽  
Rainfall Extremes ◽  
The Future ◽  
Precipitation Events

That we are in a period of extraordinary rates of climate change is today evident. These climate changes are likely to impact local weather conditions with direct impacts on precipitation patterns and urban drainage. In recent years several studies have focused on revealing the nature, extent and consequences of climate change on urban drainage and urban runoff pollution issues. This study uses predictions from a regional climate model to look at the effects of climate change on extreme precipitation events. Results are presented in terms of point rainfall extremes. The analysis involves three steps: Firstly, hourly rainfall intensities from 16 point rain gauges are averaged to create a rain gauge equivalent intensity for a 25 × 25 km square corresponding to one grid cell in the climate model. Secondly, the differences between present and future in the climate model is used to project the hourly extreme statistics of the rain gauge surface into the future. Thirdly, the future extremes of the square surface area are downscaled to give point rainfall extremes of the future. The results and conclusions rely heavily on the regional model's suitability in describing extremes at time-scales relevant to urban drainage. However, in spite of these uncertainties, and others raised in the discussion, the tendency is clear: extreme precipitation events effecting urban drainage and causing flooding will become more frequent as a result of climate change.

Understanding Precipitation Characteristics of Afghanistan at Provincial Scale

2021 ◽  
Author(s):  
Shakti Suryavanshi ◽  
Nitin Joshi ◽  
Hardeep Kumar Maurya ◽  
Divya Gupta ◽  
Keshav Kumar Sharma
Keyword(s):  
Extreme Precipitation ◽  
Asian Country ◽  
Annual Precipitation ◽  
Precipitation Pattern ◽  
Precipitation Trend ◽  
Extreme Precipitation Events ◽  
Changing Patterns ◽  
Extreme Precipitation Indices ◽  
Precipitation Indices ◽  
Precipitation Events

Abstract This study examines the pattern and trend of seasonal and annual precipitation along with extreme precipitation events in a data scare, south Asian country, Afghanistan. Seven extreme precipitation indices were considered based upon intensity, duration and frequency of precipitation events. The study revealed that precipitation pattern of Afghanistan is unevenly distributed at seasonal and yearly scales. Southern and Southwestern provinces remain significantly dry whereas, the Northern and Northeastern provinces receive comparatively higher precipitation. Spring and winter seasons bring about 80% of yearly precipitation in Afghanistan. However, a notable declining precipitation trend was observed in these two seasons. An increasing trend in precipitation was observed for the summer and autumn seasons, however; these seasons are the lean periods for precipitation. A declining annual precipitation trend was also revealed in many provinces of Afghanistan. Analysis of extreme precipitation indices reveals a general drier condition in Afghanistan. Large spatial variability was found in precipitation indices. In many provinces of Afghanistan, a significantly declining trends were observed in intensity-based (Rx1-day, RX5-day, SDII and R95p) and frequency-based (R10) precipitation indices. The duration-based precipitation indices (CDD and CWD) also infer a general drier climatic condition in Afghanistan. This study will assist the agriculture and allied sectors to take well-planned adaptive measures in dealing with the changing patterns of precipitation, and additionally, facilitating future studies for Afghanistan.

Evaluating the skill of satellite data on the individuation of extreme precipitation events in Calabria (southern Italy)

2020 ◽  
Author(s):  
Tommaso Caloiero ◽  
Roberto Coscarelli ◽  
Giulio Nils Caroletti
Keyword(s):  
Satellite Data ◽  
Extreme Precipitation ◽  
Southern Italy ◽  
Hot Spot ◽  
Rain Gauge ◽  
Precipitation Event ◽  
The European Union ◽  
Extreme Precipitation Events ◽  
Daily Data ◽  
Precipitation Events

<p>In this study, the skill of TRMM Multi-Satellite Precipitation Analysis (TMPA) data to locate spatially and temporally extreme precipitation has been tested over Calabria, a region in southern Italy.</p><p>Calabria is a very challenging region for hydrometeorology studies, as i) it is a mainly mountainous region with complex orography; ii) it is surrounded by sea, providing  an abundance of available moisture; iii) it belongs to the Mediterranean region, a hot-spot for climate change.</p><p>TMPA, which provides daily data at a 0.25° resolution (i.e., about 25 km at southern Italy latitudes), was tested with regards to three extreme precipitation events that occurred between 1998 and 2019, i.e., the years of TMPA’s operational time frame. The first event, taking place on 07-12/09/2000, lasted for several days and involved most of Calabria. The second (01-04/07/2006) was a very localized midsummer event, which hit a very small area with destructive consequences. Finally, the 18-27/11/2013 event was a ten-day long heavy precipitation event that hit the region in spots.</p><p>TMPA daily data were compared against validated and homogenized rain gauge data from 79 stations managed by the Multi-Risk Functional Centre of the Regional Agency for Environmental Protection. TMPA was evaluated both in relative and absolute terms: i) the relative skill was tested by checking if TMPA evaluated correctly the presence of extreme precipitation, defined as daily precipitation passing the 99th percentile threshold; ii) the absolute skill was tested by checking if TMPA reproduced correctly the cumulated precipitation values during the events.</p><p>TMPA proved sufficiently able to locate areas subject to heavy cumulated precipitation during large spatially distributed events over the region. However, it showed difficulties in reproducing very localized events, as the 2006 case study was not detected at all, showing that 25-km spatial resolution and daily time resolution proved inadequate to resolve this type of rainfall event.</p><p>Results might give insights into the possibility of using satellite data for real-time monitoring of extreme precipitation, especially since the transition from the old TMPA to the new Integrated Multi-satellitE Retrievals for GPM (IMERG) set was completed in January 2020.</p><p> </p><p>Acknowledgments:</p><p>The Project INDECIS is part of ERA4CS, an ERA-NET initiated by JPI Climate, and funded by FORMAS (SE), DLR (DE), BMWFW (AT), IFD (DK), MINECO (ES), ANR (FR) with co-funding by the European Union (Grant 690462).</p>

scholarly journals On the spatial and temporal variability of ENSO precipitation and drought teleconnection in mainland Southeast Asia

2015 ◽  
Vol 11 (6) ◽  
pp. 5307-5343 ◽  
Author(s):  
T. A. Räsänen ◽  
V. Lindgren ◽  
J. H. A. Guillaume ◽  
B. M. Buckley ◽  
M. Kummu
Keyword(s):  
Southeast Asia ◽  
Southern Oscillation ◽  
Drought Severity ◽  
Spatial And Temporal Variability ◽  
Severe Drought ◽  
Seasonal Evolution ◽  
Enso Events ◽  
Precipitation Anomalies ◽  
Mainland Southeast Asia

Abstract. The variability in the hydroclimate over mainland Southeast Asia is strongly influenced by the El Niño–Southern Oscillation (ENSO) phenomenon, which has been linked to severe drought and floods that profoundly influence human societies and ecosystems alike. However, the spatial characteristics and long-term stationarity of ENSO's influence in the region are not well understood. We thus aim to analyse seasonal evolution and spatial variations in the effect of ENSO on precipitation over the period of 1980–2013, and long-term variation in the ENSO-teleconnection using tree-ring derived Palmer Drought Severity Indices (PDSI) that span from 1650–2004. We found that the majority of the study area is under the influence of ENSO, which has affected the region's hydroclimate over the majority (96 %) of the 355 year study period. Our results further indicate that there is a pattern of seasonal evolution of precipitation anomalies during ENSO. However, considerable variability in the ENSO's influence is revealed: the strength of ENSO's influence was found to vary in time and space, and the different ENSO events resulted in varying precipitation anomalies. Additional research is needed to investigate how this variation in ENSO teleconnection is influenced by other factors, such as the properties of the ENSO events and other ocean and atmospheric phenomena. In general, the high variability we found in ENSO teleconnection combined with limitations of current knowledge, suggests that the adaptation to extremes in hydroclimate in mainland Southeast Asia needs to go beyond "predict-and-control" and recognise both uncertainty and complexity as fundamental principles.

Ultra-high-resolution future coupled model projections of atmospheric rivers

2020 ◽  
Author(s):  
Arjun Nellikkattil ◽  
Bin Guan ◽  
June-Yi Lee ◽  
Axel Timmermann ◽  
Sun-Seon Lee ◽  
...  
Keyword(s):  
High Resolution ◽  
Extreme Precipitation ◽  
Hydrological Cycle ◽  
Coupled Model ◽  
The United States ◽  
Horizontal Resolution ◽  
Greenhouse Warming ◽  
Polar Regions ◽  
Atmospheric Rivers ◽  
Extreme Precipitation Events

<p>Atmospheric rivers (ARs) are narrow, elongated structures, transporting large amounts of water vapor from the tropics towards polar regions. These synoptic scale features play an important role in the global hydrological cycle and for extreme precipitation events. To study how ARs will change in response to greenhouse warming we use a series of century-long fully coupled ultra-high-resolution simulations conducted with CESM 1.2.2 with an approximate horizontal resolution of ~25 km in the atmosphere and 10 km in the ocean. The simulations were carried out for present-day, 2xCO2 and 4xCO2 conditions. In this high atmospheric resolution, we obtain a much more realistic representation of complex orographic features (such as the Rocky Mountains), which can greatly influence the extreme precipitation often associated with ARs. Results from the present-day simulation are compared with ERA-Interim data to validate the model's fidelity in representing ARs. Our analysis focuses on future greenhouse-warming induced changes in AR frequency, geometry, landfalling latitude and strength. We find a global increase in the frequency of ARs amounting to ~0.5% for 2xCO2 and 0.9% for 4xCO2 respectively. In subtropical areas, such as the southwestern part of the United States AR frequencies increase by up to 7%. The presentation will further document the underlying processes for this increase.</p>

Simulating extreme precipitation over the Arabian Peninsula using a convective-permitting sub-seasonal reforecast product

2020 ◽  
Author(s):  
Thang M. Luong ◽  
Christoforus Bayu Risanto ◽  
Hsin-I Chang ◽  
Hari Prasad Dasari ◽  
Raju Attada ◽  
...  
Keyword(s):  
Extreme Events ◽  
Extreme Precipitation ◽  
Arabian Peninsula ◽  
Flash Flood ◽  
Value Added ◽  
Rain Gauge ◽  
Potential Predictability ◽  
Extreme Precipitation Events ◽  
Simulated Precipitation ◽  
Precipitation Events

<p>Despite being one of the driest places in the world, the Arabian Peninsula (AP) occasionally experiences extreme precipitation events associated with organized convections. On 25 November 2009, for instance, a cutoff low driven rainfall exceeding 140 mm over a 6-hour period triggered a flash flood event in Jeddah, Saudi Arabia, claiming hundreds of lives and substantially damaging infrastructure. Similar extreme precipitation events have occurred in subsequent years. To assess the potential predictability of extreme precipitation in the Arabian Peninsula, we perform retrospective forecast simulations for several extreme events occurring over the period 2000 to 2018, out to a sub-seasonal timescale (3-4 weeks). Using the Advanced Research version of Weather Research and Forecasting Model (WRF-ARW), we dynamically downscale 11 ensemble members of the European Centre for Medium-Range Weather Forecasts (ECMWF) sub-seasonal reforecasts at convective-permitting resolution (4 km). WRF simulated precipitation is evaluated against various precipitation products, including the Global Precipitation Measurement (GPM) system, Climate Prediction Center morphing technique (CMORPH), and the Saudi Ministry of Water and Electricity(MOWE) and the Presidency of Meteorology and Environment(PME) regional rain gauge measurements. The convective-permitting WRF simulations substantially improve the representation of precipitation relative to the ECMWF reforecast, in terms of spatial distribution and timing. A specific focus in the presentation of the results will be on the potential value added by the use of convective-permitting modeling (CPM) to forecasting extreme events at sub-seasonal timescales. The predictability of the synoptic pattern could be the key for CPM sub-seasonal-type forecast for the AP.</p>

Typological bottlenecks: How large-scale regional language typologies help us interpret global prehistory

2016 ◽  
Vol 20 (3) ◽  
Author(s):  
Roger Blench
Keyword(s):  
Southeast Asia ◽  
Large Scale ◽  
Initial Conditions ◽  
Regional Scale ◽  
Modern Humans ◽  
Regional Patterns ◽  
Human Culture ◽  
Regional Language ◽  
Mainland Southeast Asia

AbstractIt is unlikely that local or highly specific typological characteristics of language correlate with other aspects of human culture and history. However, at regional scale, the broad typology of languages does reflect bottlenecks. The paper argues that these regions of high typological similarity are due neither to chance nor long-term convergence, but reflect the initial conditions of settlement. This suggests that regions can be characterised by negative typology, i.e., the absence of globally common traits. Conversely, typological uniformity occurs in mainland Southeast Asia, a region notable for the similarities between language structures. An expansion of the remit of typology can uncover large regional patterns which can be tied to the archaeological narrative of the early expansion of modern humans.

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