scholarly journals Monitoring the Indian Summer Monsoon Evolution at the Granularity of the Indian Meteorological Sub-divisions using Remotely Sensed Rainfall Products

2019 ◽  
Vol 11 (9) ◽  
pp. 1080 ◽  
Author(s):  
Amit Bhardwaj ◽  
Vasubandhu Misra
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Spatial Scales ◽  
Tropical Rainfall Measuring Mission ◽  
Rain Gauge ◽  
Seasonal Rainfall ◽  
Onset Date ◽  
Rainfall Anomalies ◽  
Global Precipitation ◽  
Seasonal Length

We make use of satellite-based rainfall products from the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) to objectively define local onset and demise of the Indian Summer Monsoon (ISM) at the spatial resolution of the meteorological subdivisions defined by the Indian Meteorological Department (IMD). These meteorological sub-divisions are the operational spatial scales for official forecasts issued by the IMD. Therefore, there is a direct practical utility to target these spatial scales for monitoring the evolution of the ISM. We find that the diagnosis of the climatological onset and demise dates and its variations from the TMPA product is quite similar to the rain gauge based analysis of the IMD, despite the differences in the duration of the two datasets. This study shows that the onset date variations of the ISM have a significant impact on the variations of the seasonal length and seasonal rainfall anomalies in many of the meteorological sub-divisions: for example, the early or later onset of the ISM is associated with longer and wetter or shorter and drier ISM seasons, respectively. It is shown that TMPA dataset (and therefore its follow up Global Precipitation Measurement (GPM) Integrated Multi-satellite Retrievals for GPM (IMERG)) could be usefully adopted for monitoring the onset of the ISM and therefore extend its use to anticipate the potential anomalies of the seasonal length and seasonal rainfall anomalies of the ISM in many of the Indian meteorological sub-divisions.

scholarly journals Understanding the Variations of the Length and the Seasonal Rainfall Anomalies of the Indian Summer Monsoon

2017 ◽  
Vol 30 (5) ◽  
pp. 1753-1763 ◽  
Author(s):  
Vasubandhu Misra ◽  
Amit Bhardwaj ◽  
Ryne Noska
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Large Scale ◽  
Seasonal Rainfall ◽  
Boreal Summer ◽  
Equatorial Pacific Ocean ◽  
Eastern Equatorial Pacific ◽  
Rainfall Anomalies ◽  
Static Energy ◽  
Eastern Equatorial Pacific Ocean

Abstract The canonical relationship between the length and the total seasonal rainfall anomalies of the Indian summer monsoon (ISM) is the association of the longer (shorter) season with wetter (drier) seasonal rainfall anomalies. This study shows that such canonical behavior is clearly associated with relatively strong ENSO SST anomalies in the eastern equatorial Pacific Ocean that appear in the boreal summer and fall seasons. The noncanonical relationship is caused by a longer (shorter) season associated with drier (wetter) ISM seasonal rainfall anomalies. A majority of these noncanonical seasons, with anomalously short season length but anomalously high seasonal mean rain, tend to occur under relatively weak La Niña forcing during the boreal summer season. Although the onset of such seasons occurs through canonical ENSO forcing of a large-scale meridional temperature gradient, the demise is dictated by the depletion of moist static energy from the underlying cooling of the upper ocean in the northern Indian Ocean. This is due to stronger meridional Ekman ocean heat transport forced by the stronger low-level atmospheric southwesterlies than those in the corresponding canonical wet ISM season.

scholarly journals Relationship between monsoon onset over Thiruvananthapuram and Mumbai and rainfall over Kerala and Konkan

MAUSAM ◽  
2021 ◽  
Vol 57 (3) ◽  
pp. 445-450
Author(s):  
M. P. SHEWALE ◽  
A. S. PONKSHE
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Significant Relationship ◽  
Monsoon Rainfall ◽  
Indian Summer Monsoon Rainfall ◽  
Summer Monsoon Rainfall ◽  
Monsoon Onset ◽  
Onset Date ◽  
Simultaneous Occurrence

Lkkj & bl ’kks/k&Ik= esa nks LFkkuksa uker% fFk:ouUriqje vkSj eqEcbZ dk p;u djds ;g irk yxkus dk iz;kl fd;k x;k gS fd D;k ekulwu ds vkxeu dh rkjh[k dk Øze’k% dsjy vkSj dksad.k esa gksus okyh o"kkZ ds lkFk dksbZ laca/k gS A lewps ns’k ds fy, Hkkjrh; xzh"edkyhu ekulwu o"kkZ ¼vkbZ- ,l- ,e- vkj-½ ds lkFk ekulwu ds vkxeu dh rkjh[k ds laca/k dh Hkh tk¡p dh xbZ gS A bl v/;;u ds fy, 100 o"kksaZ ¼1901&2000½ ds vk¡dM+ksa dk mi;ksx fd;k x;k gS A             fo’ys"k.k dh lgk;rk ls vk¡dM+ksa dh ,d:irk vkSj o"kkZ ds vU; y{k.kksa dh tk¡p dh xbZ gS A dsjy vkSj dksad.k esa vdky vkSj ekSle laca/kh ck<+ dh ledkfyd ?kVukvksa dh vko`fr dk irk yxk;k x;k gS vkSj mldh tk¡p dh xbZ gS A             bl v/;;u ls ;g irk pyk gS fd ekulwu ds vkxeu ds laca/k esa fFk:ouUriqje vkSj eqEcbZ ds chp egRoiw.kZ laca/k gS A fFk:ouariqje vFkok eqEcbZ vkSj vkbZ- ,l- ,u- vkj- ds chp ekulwu ds vkxeu ds ckjs esa fdlh egRoiw.kZ laca/k dk irk ugha pyk gS A dsjy dh rqyuk eas dksad.k esa ekSle laca/kh ck<+ vf/kd vkrh gS A In this paper, choosing two locations viz., Thiruvananthapuram and Mumbai, an attempt has been made to find whether the onset date of monsoon has any bearing on monsoon rainfall over Kerala and Konkan respectively.   Association of the onset dates with Indian Summer Monsoon Rainfall (ISMR) for the country as a whole has also been explored.  The study utilizes 100 years’ (1901-2000) data. Homogeneity of the data and other rainfall features have been examined with the help of  analysis.  Frequency of simultaneous occurrence of droughts and meteorological floods at Kerala and Konkan have been determined and examined.    The study showed that onset over Thiruvananthapuram and Mumbai are significantly related.  It revealed absence of any significant relationship between onset over Thiruvananthapuram or Mumbai and the ISMR. Meteorological floods seem to be more frequent over Konkan compared to Kerala.

scholarly journals First-Year Evaluation of GPM Rainfall over the Netherlands: IMERG Day 1 Final Run (V03D)

2016 ◽  
Vol 17 (11) ◽  
pp. 2799-2814 ◽  
Author(s):  
M. F. Rios Gaona ◽  
A. Overeem ◽  
H. Leijnse ◽  
R. Uijlenhoet
Keyword(s):  
The Netherlands ◽  
Land Surface ◽  
Tropical Rainfall Measuring Mission ◽  
Ground Truth ◽  
Rain Gauge ◽  
First Year ◽  
Radar Rainfall ◽  
High Resolution Data ◽  
Precipitation Estimates ◽  
Global Precipitation

Abstract The Global Precipitation Measurement (GPM) mission is the successor to the Tropical Rainfall Measuring Mission (TRMM), which orbited Earth for ~17 years. With Core Observatory launched on 27 February 2014, GPM offers global precipitation estimates between 60°N and 60°S at 0.1° × 0.1° resolution every 30 min. Unlike during the TRMM era, the Netherlands is now within the coverage provided by GPM. Here the first year of GPM rainfall retrievals from the 30-min gridded Integrated Multisatellite Retrievals for GPM (IMERG) product Day 1 Final Run (V03D) is assessed. This product is compared against gauge-adjusted radar rainfall maps over the land surface of the Netherlands at 30-min, 24-h, monthly, and yearly scales. These radar rainfall maps are considered to be ground truth. The evaluation of the first year of IMERG operations is done through time series, scatterplots, empirical exceedance probabilities, and various statistical indicators. In general, there is a tendency for IMERG to slightly underestimate (2%) countrywide rainfall depths. Nevertheless, the relative underestimation is small enough to propose IMERG as a reliable source of precipitation data, especially for areas where rain gauge networks or ground-based radars do not offer these types of high-resolution data and availability. The potential of GPM for rainfall estimation in a midlatitude country is confirmed.

scholarly journals Comparison of Global Precipitation Estimates across a Range of Temporal and Spatial Scales

2016 ◽  
Vol 29 (21) ◽  
pp. 7773-7795 ◽  
Author(s):  
Maria Gehne ◽  
Thomas M. Hamill ◽  
George N. Kiladis ◽  
Kevin E. Trenberth
Keyword(s):  
Time Scales ◽  
Large Scale ◽  
Global Climate ◽  
Spatial Scales ◽  
Rain Gauge ◽  
Random Errors ◽  
Climate Data ◽  
Precipitation Estimates ◽  
Global Precipitation ◽  
Daily Time

Abstract Characteristics of precipitation estimates for rate and amount from three global high-resolution precipitation products (HRPPs), four global climate data records (CDRs), and four reanalyses are compared. All datasets considered have at least daily temporal resolution. Estimates of global precipitation differ widely from one product to the next, with some differences likely due to differing goals in producing the estimates. HRPPs are intended to produce the best snapshot of the precipitation estimate locally. CDRs of precipitation emphasize homogeneity over instantaneous accuracy. Precipitation estimates from global reanalyses are dynamically consistent with the large-scale circulation but tend to compare poorly to rain gauge estimates since they are forecast by the reanalysis system and precipitation is not assimilated. Regional differences among the estimates in the means and variances are as large as the means and variances, respectively. Even with similar monthly totals, precipitation rates vary significantly among the estimates. Temporal correlations among datasets are large at annual and daily time scales, suggesting that compensating bias errors at annual and random errors at daily time scales dominate the differences. However, the signal-to-noise ratio at intermediate (monthly) time scales can be large enough to result in high correlations overall. It is shown that differences on annual time scales and continental regions are around 0.8 mm day−1, which corresponds to 23 W m−2. These wide variations in the estimates, even for global averages, highlight the need for better constrained precipitation products in the future.

scholarly journals Study of the microphysical properties associated with the Monsoon Intraseasonal Oscillation as seen from the TRMM observations

2012 ◽  
Vol 30 (6) ◽  
pp. 897-910 ◽  
Author(s):  
M. Halder ◽  
P. Mukhopadhyay ◽  
S. Halder
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Liquid Water ◽  
Tropical Rainfall Measuring Mission ◽  
Cloud Water ◽  
Cloud Liquid Water ◽  
Tropical Rainfall ◽  
Intraseasonal Oscillations ◽  
Cloud Ice

Abstract. The spatio-temporal variability of Indian Summer Monsoon is well studied based on different types of rainfall data. However, very few attempts have been made to study the underlying role of clouds and its hydrometeors on Monsoon Intraseasonal Oscillations. The northward propagating Monsoon Intraseasonal Oscillations and its characteristics remain a challenge for the numerical modelers even today. In view of this, we have set out to analyze the role of cloud hydrometeors and their linkage with northward propagating Monsoon Intraseasonal Oscillations. The science question that we intend to address here is whether the different phases of the cloud hydrometeors show similar propagation characteristics as that of rainfall, and what are the relations of their phases with the convection centre using Tropical Rainfall Measuring Mission data. In answering the question, we have analyzed ten years of Tropical Rainfall Measuring Mission 2A12 hydrometeor data over Indian region. Our analyses show that the cloud water and cloud ice do show a large scale organization during the Indian Summer Monsoon regime of June–September, and systematically progress northward getting initiated over equatorial Indian Ocean. On further analyses, we found that cloud water actually leads the rainfall and cloud ice lags the rainfall. We have further demonstrated the process by analyzing dynamical parameters from Modern Era-Retrospective Analysis for Research and Applications. The presence of cloud water in the lower troposphere in the leading edge of rainfall indicates the lower level moistening and preconditioning of the convective instability due to enhanced moisture convergence. Subsequently, deep convection is triggered, which generates hydrometeor above freezing level and cloud ice in the upper troposphere. To quantify objectively the relation among cloud liquid water, cloud ice and rainfall, the lag correlation is computed with respect to convection center, where the above hypothesis is established that cloud liquid water leads the rainfall and cloud ice lag. This relation among hydrometeors may help the numerical modelers to incorporate such processes for capturing the characteristics of Monsoon Intraseasonal Oscillations.

scholarly journals Evaluation of GPM-era Global Satellite Precipitation Products over Multiple Complex Terrain Regions

2019 ◽  
Vol 11 (24) ◽  
pp. 2936 ◽  
Author(s):  
Yagmur Derin ◽  
Emmanouil Anagnostou ◽  
Alexis Berne ◽  
Marco Borga ◽  
Brice Boudevillain ◽  
...  
Keyword(s):  
Tropical Rainfall Measuring Mission ◽  
Rain Gauge ◽  
Great Success ◽  
Precipitation Data ◽  
Mountainous Regions ◽  
Orographic Rainfall ◽  
Error Metrics ◽  
Daily Precipitation Data ◽  
Almost All ◽  
Global Precipitation

The great success of the Tropical Rainfall Measuring Mission (TRMM) and its successor Global Precipitation Measurement (GPM) has accelerated the development of global high-resolution satellite-based precipitation products (SPP). However, the quantitative accuracy of SPPs has to be evaluated before using these datasets in water resource applications. This study evaluates the following GPM-era and TRMM-era SPPs based on two years (2014–2015) of reference daily precipitation data from rain gauge networks in ten mountainous regions: Integrated Multi-SatellitE Retrievals for GPM (IMERG, version 05B and version 06B), National Oceanic and Atmospheric Administration (NOAA)/Climate Prediction Center Morphing Method (CMORPH), Global Satellite Mapping of Precipitation (GSMaP), and Multi-Source Weighted-Ensemble Precipitation (MSWEP), which represents a global precipitation data-blending product. The evaluation is performed at daily and annual temporal scales, and at 0.1 deg grid resolution. It is shown that GSMaPV07 surpass the performance of IMERGV06B Final for almost all regions in terms of systematic and random error metrics. The new orographic rainfall classification in the GSMaPV07 algorithm is able to improve the detection of orographic rainfall, the rainfall amounts, and error metrics. Moreover, IMERGV05B showed significantly better performance, capturing the lighter and heavier precipitation values compared to IMERGV06B for almost all regions due to changes conducted to the morphing, where motion vectors are derived using total column water vapor for IMERGV06B.

Seasonal prediction of Indian Summer Monsoon onset with machine learning

2021 ◽  
Author(s):  
Takahito Mitsui ◽  
Niklas Boers
Keyword(s):  
Time Scales ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Water Resource Management ◽  
Prediction Models ◽  
Indian Subcontinent ◽  
Weather Prediction ◽  
Seasonal Prediction ◽  
Onset Date ◽  
Summer Monsoon Onset

&lt;p&gt;The prediction of the onset date of the Indian Summer Monsoon (ISM) is crucial for effective agricultural planning and water resource management on the Indian subcontinent, with more than one billion inhabitants. Existing approaches focus on extended-range to subseasonal forecasts, i.e., provide skillful predictions of the ISM onset date at horizons of 10 to 60 days. Here we propose a method for ISM onset prediction and show that it has high forecast skill at longer, seasonal time scales. The method is based on recurrent neural networks and allows for ensemble forecasts to quantify uncertainties. Our approach outperforms state-of-the-art numerical weather prediction models at comparable or longer lead times. To our knowledge, there is no statistical forecasting approach at comparable, seasonal time scales. Our results suggest that predictability of the ISM onset emerges earlier than previously assumed.&lt;/p&gt;

Characterizing the Local Variations of the Northern Australian Rainy Season

2021 ◽  
Author(s):  
John Uehling ◽  
Vasubandhu Misra ◽  
Amit Bhardwaj ◽  
Nirupam Karmakar
Keyword(s):  
Spatial Heterogeneity ◽  
Rainy Season ◽  
Winter Season ◽  
Intraseasonal Oscillation ◽  
Seasonal Rainfall ◽  
Onset Date ◽  
Boreal Winter ◽  
Rainfall Analysis ◽  
Rainfall Anomalies ◽  
Definition Of

AbstractIn this study, we introduce a localized definition of the onset and retreat of the Northern Australian rainy season that is solely based on gridded rainfall analysis. Our analysis shows that the local onset/retreat of the rainy season has considerable spatial heterogeneity. Onset is earlier and length of the rainy season is longer, west of the Gulf of Carpentaria than to its east. Furthermore, we also find the local onset/retreat is influenced by the wet and the dry spells of the 30-60 days intraseasonal oscillation. Much of the retreat of the rainy season occurs in the dry phases of the intraseasonal oscillation. However, intriguingly a majority of the local onset of the rainy season occurs during dry phases of the intraseasonal oscillation. The ENSO teleconnection with the variable length Northern Australian rainy season also exhibits spatial heterogeneity and significant differences from rainfall anomalies using the fixed-length boreal winter season. The onset, the retreat, the length, and the seasonal rainfall anomalies of the rainy season display a stronger correlation with the ENSO SST anomalies for the region east of 140°E relative to its west. The strong co-variability of the local onset date with the corresponding seasonal length and seasonal rainfall anomalies over Northern Australia offers the advantage of monitoring the onset of the Northern Australian rainy season to provide an outlook for the forthcoming season. The proposed local definition of onset/retreat of the Northern Australian rainy season is simple, objective, and unambiguous and is ideally suited for real-time monitoring of the evolution of the season.

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