scholarly journals ANALISIS PENGARUH EL NINO TERHADAP HUJAN DI NTT

2018 ◽  
Vol 3 (2) ◽  
pp. 155-162
Author(s):  
Maria Marselina Kain ◽  
Abdul Wahid ◽  
Apolonaris S. Geru
Keyword(s):  
Water Vapor ◽  
El Niño ◽  
Rainy Season ◽  
El Nino ◽  
Comparative Method ◽  
Comparison And Analysis ◽  
Rain Data

Abstrak Telah dilakukan penelitian tentang pengaruh El Nino Terhadap Hujan di NTT yang terdiri dari 23 Zona Musim dan dianalisis berdasarkan data Curah Hujan tujuh tahun terakhir kejadian El Nino terhadap data Normal selama 30 tahun. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh El Nino terhadap Awal Musim Hujan, Periode Musim Hujan, Panjang Musim Hujan, Curah Hujan Musim Hujan dan Sifat Hujan. Metode yang digunakan dalam penelitian ini adalah metode komparatif atau perbandingan dan Analisis Curah Hujan tahun El Nino  pada tujuh kali kejadian terhadap Normal Hujan selama 30 tahun. Hasil yang diperoleh dari penelitian ini adalah pada tahun terjadi El Nino, sebagian besar ZOM di NTT  dengan Awal Musim Hujan lebih mundur dari Normal, Periode Musim Hujan lebih pendek dari Normal serta Curah Hujan berkurang dari Normal dan Sifat Hujan menjadi di Bawah Normal. Pengaruh kejadian El Nino terhadap Awal Musim Hujan yang lebih mundur dari Normalnya, Periode Musim Hujan yang lebih pendek dari Normalnya dan Sifat Hujan yang di Bawah Normal dari 23 Zona di NTT pada tahun-tahun kejadian El Nino bervariasi dan ZOM yang dipengaruhi kejadian El Nino tidak tetap. Kata kunci : El Nino, Awal Musim Hujan, Periode Musim Hujan, Sifat Hujan. Abstract [Analysis Of The Influence Of El Nino On Rain In NTT] Studies have been conducted about the influence of El Nino on Rain the province which consists of 23 Zones the Season and analyzed based on Rain data for the last seven years the incidence of El Nino against Normal data for 30 years. The purpose  of this studyis to determine the effect of El Nino to the Beginning of the Rainy Season, Long Rainy Season, Precipitation of the Rainy Season and the Nature of the Rain. The method used in this research is the comparative method or comparison and Analysis of precipitation is the year of El Nino on the seven times genesis against the Normal Rain for 30 years. The results obtained from this research is that in the event of El Nino, most of the ZOM in NTT with the Beginning of the Rainy Season is more bacward than Normal, the Period of the Rainy Season is horter than Normal and precipitation is reduced from the Normal and the Nature of Rain to be Below Normal.this is because in the event of El Nino, monsoons coming from the Southest bring the water vapor that a lot of most of the turn toward the coast of Peru. The influence of El Nino to the Beginning of the Rainy Season which is backwards from Normal, the Period of the Rainy Season is shorter than Normal and the Nature of the Rainfall Below Normal from the 23 Zones in the province in the years of El Nino are varied and ZOM that influence the incidence of El Nino is not fixed. Keywords: El Nino, the Beginning of the Rainy Season, the Period of the Rainy Season, the Nature of the Rain

scholarly journals ANALISIS PENGARUH EL NINO TERHADAP HUJAN DI NTT

2018 ◽  
Vol 3 (3) ◽  
pp. 155-162
Author(s):  
Maria Marselina Kain ◽  
Abdul Wahid ◽  
Apolonaris S. Geru
Keyword(s):  
Water Vapor ◽  
El Niño ◽  
Rainy Season ◽  
El Nino ◽  
Comparative Method ◽  
Comparison And Analysis ◽  
Rain Data

Abstrak Telah dilakukan penelitian tentang pengaruh El Nino Terhadap Hujan di NTT yang terdiri dari 23 Zona Musim dan dianalisis berdasarkan data Curah Hujan tujuh tahun terakhir kejadian El Nino terhadap data Normal selama 30 tahun. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh El Nino terhadap Awal Musim Hujan, Periode Musim Hujan, Panjang Musim Hujan, Curah Hujan Musim Hujan dan Sifat Hujan. Metode yang digunakan dalam penelitian ini adalah metode komparatif atau perbandingan dan Analisis Curah Hujan tahun El Nino  pada tujuh kali kejadian terhadap Normal Hujan selama 30 tahun. Hasil yang diperoleh dari penelitian ini adalah pada tahun terjadi El Nino, sebagian besar ZOM di NTT  dengan Awal Musim Hujan lebih mundur dari Normal, Periode Musim Hujan lebih pendek dari Normal serta Curah Hujan berkurang dari Normal dan Sifat Hujan menjadi di Bawah Normal. Pengaruh kejadian El Nino terhadap Awal Musim Hujan yang lebih mundur dari Normalnya, Periode Musim Hujan yang lebih pendek dari Normalnya dan Sifat Hujan yang di Bawah Normal dari 23 Zona di NTT pada tahun-tahun kejadian El Nino bervariasi dan ZOM yang dipengaruhi kejadian El Nino tidak tetap. Kata kunci : El Nino, Awal Musim Hujan, Periode Musim Hujan, Sifat Hujan. Abstract [Analysis Of The Influence Of El Nino On Rain In NTT] Studies have been conducted about the influence of El Nino on Rain the province which consists of 23 Zones the Season and analyzed based on Rain data for the last seven years the incidence of El Nino against Normal data for 30 years. The purpose  of this studyis to determine the effect of El Nino to the Beginning of the Rainy Season, Long Rainy Season, Precipitation of the Rainy Season and the Nature of the Rain. The method used in this research is the comparative method or comparison and Analysis of precipitation is the year of El Nino on the seven times genesis against the Normal Rain for 30 years. The results obtained from this research is that in the event of El Nino, most of the ZOM in NTT with the Beginning of the Rainy Season is more bacward than Normal, the Period of the Rainy Season is horter than Normal and precipitation is reduced from the Normal and the Nature of Rain to be Below Normal.this is because in the event of El Nino, monsoons coming from the Southest bring the water vapor that a lot of most of the turn toward the coast of Peru. The influence of El Nino to the Beginning of the Rainy Season which is backwards from Normal, the Period of the Rainy Season is shorter than Normal and the Nature of the Rainfall Below Normal from the 23 Zones in the province in the years of El Nino are varied and ZOM that influence the incidence of El Nino is not fixed. Keywords: El Nino, the Beginning of the Rainy Season, the Period of the Rainy Season, the Nature of the Rain

Resolving Contrasting Regional Rainfall Responses to El Niño over Tropical Africa

2016 ◽  
Vol 29 (4) ◽  
pp. 1461-1476 ◽  
Author(s):  
Pradipta Parhi ◽  
Alessandra Giannini ◽  
Pierre Gentine ◽  
Upmanu Lall
Keyword(s):  
Water Vapor ◽  
Indian Ocean ◽  
North Atlantic ◽  
El Niño ◽  
Rainy Season ◽  
El Nino ◽  
Sea Surface ◽  
Eastern Africa ◽  
Surface Warming ◽  
Western Sahel

Abstract The evolution of El Niño can be separated into two phases—namely, growth and mature—depending on whether the regional sea surface temperature has adjusted to the tropospheric warming in the remote tropics (tropical regions away from the central and eastern tropical Pacific Ocean). The western Sahel’s main rainy season (July–September) is shown to be affected by the growth phase of El Niño through (i) a lack of neighboring North Atlantic sea surface warming, (ii) an absence of an atmospheric column water vapor anomaly over the North Atlantic and western Sahel, and (iii) higher atmospheric vertical stability over the western Sahel, resulting in the suppression of mean seasonal rainfall as well as number of wet days. In contrast, the short rainy season (October–December) of tropical eastern Africa is impacted by the mature phase of El Niño through (i) neighboring Indian Ocean sea surface warming, (ii) positive column water vapor anomalies over the Indian Ocean and tropical eastern Africa, and (iii) higher atmospheric vertical instability over tropical eastern Africa, leading to an increase in the mean seasonal rainfall as well as in the number of wet days. While the modulation of the frequency of wet days and seasonal mean accumulation is statistically significant, daily rainfall intensity (for days with rainfall > 1 mm day−1), whether mean, median, or extreme, does not show a significant response in either region. Hence, the variability in seasonal mean rainfall that can be attributed to the El Niño–Southern Oscillation phenomenon in both regions is likely due to changes in the frequency of rainfall.

scholarly journals Estimates of the Water Vapor Climate Feedback during El Niño–Southern Oscillation

2009 ◽  
Vol 22 (23) ◽  
pp. 6404-6412 ◽  
Author(s):  
A. E. Dessler ◽  
S. Wong
Keyword(s):  
Global Warming ◽  
Water Vapor ◽  
El Niño ◽  
Climate Models ◽  
El Nino ◽  
Southern Oscillation ◽  
Specific Humidity ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Water Vapor Feedback

Abstract The strength of the water vapor feedback has been estimated by analyzing the changes in tropospheric specific humidity during El Niño–Southern Oscillation (ENSO) cycles. This analysis is done in climate models driven by observed sea surface temperatures [Atmospheric Model Intercomparison Project (AMIP) runs], preindustrial runs of fully coupled climate models, and in two reanalysis products, the 40-yr European Centre for Medium-Range Weather Forecasts Re-Analysis (ERA-40) and the NASA Modern Era Retrospective-Analysis for Research and Applications (MERRA). The water vapor feedback during ENSO-driven climate variations in the AMIP models ranges from 1.9 to 3.7 W m−2 K−1, in the control runs it ranges from 1.4 to 3.9 W m−2 K−1, and in the ERA-40 and MERRA it is 3.7 and 4.7 W m−2 K−1, respectively. Taken as a group, these values are higher than previous estimates of the water vapor feedback in response to century-long global warming. Also examined is the reason for the large spread in the ENSO-driven water vapor feedback among the models and between the models and the reanalyses. The models and the reanalyses show a consistent relationship between the variations in the tropical surface temperature over an ENSO cycle and the radiative response to the associated changes in specific humidity. However, the feedback is defined as the ratio of the radiative response to the change in the global average temperature. Differences in extratropical temperatures will, therefore, lead to different inferred feedbacks, and this is the root cause of spread in feedbacks observed here. This is also the likely reason that the feedback inferred from ENSO is larger than for long-term global warming.

scholarly journals Water vapor anomaly over the tropical western Pacific in El Niño winters from radiosonde and satellite observations

2021 ◽  
Author(s):  
Minkang Du ◽  
Kaiming Huang ◽  
Shaodong Zhang ◽  
Chunming Huang ◽  
Yun Gong ◽  
...  
Keyword(s):  
Water Vapor ◽  
El Niño ◽  
El Nino ◽  
Walker Circulation ◽  
Western Pacific ◽  
Monsoon Circulation ◽  
Circulation Anomaly ◽  
Tropical Western Pacific ◽  
Ep El Niño ◽  
The Walker Circulation

Abstract. Using radiosonde observations at five stations in the tropical western Pacific and reanalysis data for 15 years from 2005 to 2019, we report an extremely negative anomaly in atmospheric water vapor during the super El Niño winter of 2015/16, and compare the anomaly with that in the other three El Niño winters. Strong specific humidity anomaly is concentrated below 8 km of the troposphere with a peak at 2.5–3.5 km, and column integrated water vapor mass anomaly over the five radiosonde sites has a large negative correlation coefficient of −0.63 with oceanic Niño3.4 index, but with a lag of about 2–3 months. In general, the tropical circulation anomaly in the El Niño winter is characterized by divergence (convergence) in the lower troposphere over the tropical western (eastern) Pacific, thus the water vapor decreases over the tropical western Pacific as upward motion is suppressed. The variability of the Hadley circulation is quite small and has little influence on the observed water vapor anomaly. The anomaly of the Walker circulation makes a considerable contribution to the total anomaly in all the four El Niño winters, especially in the 2006/07 and 2015/16 eastern-Pacific (EP) El Niño events. The monsoon circulation shows a remarkable change from one to the other event, and its anomaly is large in the 2009/10 and 2018/19 central-Pacific (CP) El Niño winters and small in the two EP El Niño winters. The observed water vapor anomaly is caused mainly by the Walker circulation anomaly in the supper EP event of 2015/16 but by the monsoon circulation anomaly in the strong CP event of 2009/10. Owing to the anomalous decrease in upward transport of water vapor during the El Niño winter, less cloud amount and more outgoing longwave radiation over the five stations are clearly presented in satellite observation.

The role of El Niño Southern Oscillation on the patterns of cycling rates observed over India during the monsoon season

2014 ◽  
Vol 5 (4) ◽  
pp. 696-706 ◽  
Author(s):  
T. V. Lakshmi Kumar ◽  
K. Koteswara Rao ◽  
R. Uma ◽  
K. Aruna
Keyword(s):  
Water Vapor ◽  
El Niño ◽  
Hydrological Cycle ◽  
El Nino ◽  
Southern Oscillation ◽  
Monsoon Season ◽  
Precipitable Water ◽  
Spatiotemporal Variability ◽  
Monsoon Period ◽  
Sw Monsoon

Trend and interannual variability of total integrated precipitable water vapor (PWV) has been studied over India for the period 1979–2004 using NCEP/National Centre for Atmospheric Research reanalysis data with 2.5° × 2.5° resolution. The spatiotemporal variability of cycling rates (CR; units: per day), obtained from the ratio of rainfall to the PWV were presented not only for the long term (1979–2004) but also during El Niño (EN) and La Niña (LN) years of the study period to understand the intensity of hydrological cycle. The paper then dwells on obtaining the monthly atmospheric residences times over India to infer the stay of water vapor before it precipitates. The results of the present study are: all India PWV shows decreasing trend in association with the increasing/decreasing trends of Niño 3 SST/Southern Oscillation Index (SOI) for the southwest (SW) monsoon period of 1979–2004; the spatial pattern of temporal correlations of CR with SOI and Niño 3 SST displayed the significant positive and negative values in peninsular and central Indian portions of India respectively; all India atmospheric residence times varied from 9 to 2 days from premonsoon/post monsoon to SW monsoon over India.

scholarly journals Predictability of Persistent Thailand Rainfall during the Mature Monsoon Season in 2011 Using Statistical Downscaling of CGCM Seasonal Prediction

2015 ◽  
Vol 143 (4) ◽  
pp. 1166-1178 ◽  
Author(s):  
Yukiko Imada ◽  
Shinjiro Kanae ◽  
Masahide Kimoto ◽  
Masahiro Watanabe ◽  
Masayoshi Ishii
Keyword(s):  
Statistical Downscaling ◽  
El Niño ◽  
Rainy Season ◽  
El Nino ◽  
Seasonal Prediction ◽  
Precipitation Pattern ◽  
Prediction System ◽  
Central Pacific ◽  
Central Pacific El Niño ◽  
Local Rainfall

Abstract Predictability of above-normal rainfall over Thailand during the rainy season of 2011 was investigated with a one-tier seasonal prediction system based on an atmosphere–ocean coupled general circulation model (CGCM) combined with a statistical downscaling method. The statistical relationship was derived using singular value decomposition analysis (SVDA) between observed regional rainfall and the hindcast of tropical sea surface temperature (SST) from the seasonal prediction system, which has an ability to forecast oceanic variability for lead times up to several months. The downscaled product of 2011 local rainfall was obtained by combining rainfall patterns derived from significant modes of SVDA. This method has the advantage in terms of flexibility that phenomenon-based statistical relationships, such as teleconnections associated with El Niño–Southern Oscillation (ENSO), Indian Ocean dipole (IOD), or the newly recognized central Pacific El Niño, are considered separately in each SVDA mode. The downscaled prediction initialized from 1 August 2011 reproduced the anomalously intense precipitation pattern over Indochina including northern Thailand during the latter half of the rainy season, even though the direct hindcast from the CGCM failed to predict the local rainfall distribution and intensity. Further analysis revealed that this method is applicable to the other recent events such as heavy rainfall during the rainy seasons of 2002 and 2008 in Indochina.

Spatial and temporal variation in precipitation at the start of the rainy season in tropical Australia

2010 ◽  
Vol 32 (2) ◽  
pp. 215 ◽  
Author(s):  
S. T. Garnett ◽  
G. Williamson
Keyword(s):  
Seed Germination ◽  
El Niño ◽  
Rainy Season ◽  
El Nino ◽  
Southern Oscillation ◽  
Temporal Trends ◽  
Spatial And Temporal Variation ◽  
Economic Implications ◽  
North West ◽  
The North

The patterns of rainfall early in the rainy season vary substantially across northern Australia, even in sites with the same annual average. This has biophysical and economic implications in terms of land and infrastructure management, resource availability and capacity, and access. Daily patterns in long-term rainfall records in Australia north of 23°S subject to regular monsoonal rainfall were compared with threshold levels for dryland and wetland seed germination, initiation of the growing season, patterns of gaps between early storms and the heaviness of the first falls, correlations between thresholds, spatial variation in correlation with the Southern Oscillation Index (SOI) and temporal trends in mean threshold dates. The earliest rains sufficient to cause seed germination or generate fresh fodder occur in the north-west of the Northern Territory with the average date being later to the south, east and west. Initial falls of the rainy season are heaviest, however, on Cape York Peninsula so that the time between first falls and saturation is shortest in the east. The probability of extended gaps between rainfall events increased from north to south. When the SOI is taken into account, no change in timing could be detected at the few sites with records of sufficient duration. However, because of changes in SOI frequency, rains are tending to start earlier in the drier parts of the north and north-west and later in the east. This may be because anthropogenic climate change is resulting in fewer classical El Niño Southern Oscillation events and more frequent El Niño Modoki climate anomalies.

scholarly journals Interpretation of Enhanced Integrated Water Vapor Bands Associated with Extratropical Cyclones: Their Formation and Connection to Tropical Moisture

2006 ◽  
Vol 134 (4) ◽  
pp. 1063-1080 ◽  
Author(s):  
J-W. Bao ◽  
S. A. Michelson ◽  
P. J. Neiman ◽  
F. M. Ralph ◽  
J. M. Wilczak
Keyword(s):  
Water Vapor ◽  
El Niño ◽  
Trajectory Analysis ◽  
El Nino ◽  
Weather Prediction ◽  
Moisture Convergence ◽  
Eastern Pacific ◽  
Extratropical Cyclones ◽  
The Tropics ◽  
Tropical Moisture

Abstract Trajectory analysis using a weather prediction model is performed for five cases to interpret the formation of enhanced bands of vertically integrated water vapor (IWV) in the central and eastern Pacific that are frequently seen in satellite images from the Special Sensor Microwave Imager. The connection of these enhanced bands with poleward water vapor transport from the Tropics is also examined. It is shown that the leading end of the enhanced IWV bands (defined as the most eastward and poleward end) is the manifestation of moisture convergence in the warm conveyor belt associated with extratropical cyclones, while the bands away from the leading end result mainly from moisture convergence along the trailing cold fronts. There is evidence that some enhanced IWV bands may be associated with a direct poleward transport of tropical moisture along the IWV bands from the Tropics all the way to the extratropics. The trajectory analysis, together with the seasonal mean sea level pressure analysis, indicates that a favorable condition for the occurrence of a direct, along-IWV band transport of tropical (defined as south of 23.5°N) moisture to the U.S. West Coast in the eastern Pacific is a weakened subtropical ridge in the central Pacific with an enhanced southwesterly low-level flow. The authors hypothesize that the direct poleward transport of tropical moisture within an enhanced IWV band in the eastern Pacific is most possible in the neutral El Niño–Southern Oscillation (ENSO) phase and is least possible in the El Niño phase.

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