scholarly journals Linkages of Active and Weakening MJO events to Seasonal Variations over the Maritime Continent

2021 ◽  
Vol 925 (1) ◽  
pp. 012004
Author(s):  
A Lumbangaol ◽  
I M Radjawane ◽  
A Furqon
Keyword(s):  
Seasonal Variations ◽  
Large Scale ◽  
Longwave Radiation ◽  
Tropical Rainfall Measuring Mission ◽  
Physical Sciences ◽  
Maritime Continent ◽  
Rainfall Events ◽  
Daily Data ◽  
June July ◽  
Rain Rates

Abstract The Madden-Julian Oscillation (MJO) is a large-scale phenomenon of air-sea intra-seasonal variability in the equatorial area, particularly in the Maritime Continent (MC). This research focused on the analysis of the MJO propagation process in association with rainfall events and sea surface temperature anomaly (SSTA) during seasonal variations, i.e., November, December, January February, and March (NDJFM), and May, June, July, August September (MJJAS). MJO events from 2010 to 2019 were classified as MJO active or MJO weakening according to propagation characteristics and amplitude changes in the RMM index. This research uses a dataset of 10-year series of daily Tropical Rainfall Measuring Mission (TRMM) (3B42 V7 derived) measurements for detecting rain rates. Daily OLR data from the NOAA Physical Sciences Laboratory and SSTA daily data from Physical Oceanography Distributed Active Archive Centre (PODAAC) NOAA are considered for analysing MJO propagation. Composites of outgoing longwave radiation (OLR) were also identified differences between the two events; active MJO events had consistently higher negative OLR anomalies than weakening MJO events. Active MJO events during NDJFM had a higher rain rate and positive SSTA than weakening MJO events. Furthermore, composite rain rates distribution over MC during NDJFM are mainly located in the south of the equator, contrarily when MJJAS are north of the equator.

scholarly journals Large-Scale Environmental Characteristics of MJOs that Strengthen and Weaken over the Maritime Continent

2018 ◽  
Vol 31 (14) ◽  
pp. 5731-5748 ◽  
Author(s):  
Casey D. Burleyson ◽  
Samson M. Hagos ◽  
Zhe Feng ◽  
Brandon W. J. Kerns ◽  
Daehyun Kim
Keyword(s):  
Seasonal Cycle ◽  
Large Scale ◽  
Longwave Radiation ◽  
Sea Surface ◽  
Madden Julian Oscillation ◽  
Moist Static Energy ◽  
Maritime Continent ◽  
New Finding ◽  
Field Campaigns ◽  
Static Energy

Abstract The characteristics of Madden–Julian oscillation (MJO) events that strengthen and weaken over the Maritime Continent (MC) are examined. The real-time multivariate MJO (RMM) index is used to assess changes in global MJO amplitude over the MC. The MJO weakens at least twice as often as it strengthens over the MC, with weakening MJOs being twice as likely during El Niño compared to La Niña years and the reverse for strengthening events. MJO weakening shows a pronounced seasonal cycle that has not been previously documented. During the Northern Hemisphere (NH) summer and fall the RMM index can strengthen over the MC. MJOs that approach the MC during the NH winter typically weaken according to the RMM index. This seasonal cycle corresponds to whether the MJO crosses the MC primarily north or south of the equator. Because of the seasonal cycle, weakening MJOs are characterized by positive sea surface temperature and moist-static energy anomalies in the Southern Hemisphere (SH) of the MC compared to strengthening events. Analysis of the outgoing longwave radiation (OLR) MJO index (OMI) shows that MJO precipitation weakens when it crosses the MC along the equator. A possible explanation of this based on previous results is that the MJO encounters more landmasses and taller mountains when crossing along the equator or in the SH. The new finding of a seasonal cycle in MJO weakening over the MC highlights the importance of sampling MJOs throughout the year in future field campaigns designed to study MJO–MC interactions.

Estimates of Tropical Diabatic Heating Profiles: Commonalities and Uncertainties

2010 ◽  
Vol 23 (3) ◽  
pp. 542-558 ◽  
Author(s):  
Samson Hagos ◽  
Chidong Zhang ◽  
Wei-Kuo Tao ◽  
Steve Lang ◽  
Yukari N. Takayabu ◽  
...  
Keyword(s):  
Large Scale ◽  
Diabatic Heating ◽  
Tropical Rainfall Measuring Mission ◽  
Upper Troposphere ◽  
Tropical Oceans ◽  
Field Campaigns ◽  
Heating Profiles ◽  
The Tropics ◽  
Rain Rates

Abstract This study aims to evaluate the consistency and discrepancies in estimates of diabatic heating profiles associated with precipitation based on satellite observations and microphysics and those derived from the thermodynamics of the large-scale environment. It presents a survey of diabatic heating profile estimates from four Tropical Rainfall Measuring Mission (TRMM) products, four global reanalyses, and in situ sounding measurements from eight field campaigns at various tropical locations. Common in most of the estimates are the following: (i) bottom-heavy profiles, ubiquitous over the oceans, are associated with relatively low rain rates, while top-heavy profiles are generally associated with high rain rates; (ii) temporal variability of latent heating profiles is dominated by two modes, a deep mode with a peak in the upper troposphere and a shallow mode with a low-level peak; and (iii) the structure of the deep modes is almost the same in different estimates and different regions in the tropics. The primary uncertainty is in the amount of shallow heating over the tropical oceans, which differs substantially among the estimates.

Comparison of TRMM-Derived Rainfall Products for General and Extreme Rains over the Maritime Continent

2017 ◽  
Vol 56 (7) ◽  
pp. 1867-1881 ◽  
Author(s):  
Andung Bayu Sekaranom ◽  
Hirohiko Masunaga
Keyword(s):  
Rain Rate ◽  
Tropical Rainfall Measuring Mission ◽  
Maritime Continent ◽  
Brightness Temperatures ◽  
Extreme Rain ◽  
Trmm Precipitation ◽  
Precipitation Analysis ◽  
Microwave Imager ◽  
Trmm Microwave Imager ◽  
Rain Rates

AbstractProperties of the rain estimation differences between Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) 2A25, TRMM Microwave Imager (TMI) 2A12, and TRMM Multisatellite Precipitation Analysis (TMPA) 3B42 are investigated with a focus on distinguishing between nonextreme and extreme rains over the Maritime Continent from 1998 to 2014. Statistical analyses of collocated TMI 1B11 85-GHz polarization-corrected brightness temperatures, PR 2A23 storm-top heights, and PR 2A25 vertical rain profiles are conducted to identify possible sources of the differences. The results indicate that a large estimation difference exists between PR and TMI for the general rain rate (extreme and nonextreme events). The PR–TMI rain-rate differences are larger over land and coast than over ocean. When extreme rain is isolated, a higher frequency of occurrence is identified by PR over ocean, followed by TMI and TMPA. Over land, TMI yields higher rain frequencies than PR with an intermediate range of rain rates (between 15 and 25 mm h−1), but it gives way to PR for the highest extremes. The turnover at the highest rain rates arises because the heaviest rain depicted by PR does not necessarily accompany the strongest ice-scattering signals, which TMI relies on for estimating precipitation over land and coast.

scholarly journals Extreme precipitation over Indonesian maritime continent: Uncertainties in satellite estimation and its relationship with low storm top height extreme

2018 ◽  
Author(s):  
Sekaranom A.B.
Keyword(s):  
Extreme Precipitation ◽  
Land Surface ◽  
Tropical Rainfall Measuring Mission ◽  
Middle Part ◽  
Lower Amount ◽  
Maritime Continent ◽  
Near Surface ◽  
Low Cloud ◽  
Microwave Imager ◽  
Rain Rates

This paper aims to explain the uncertainties in satellite rainfall estimation due to existence of very high near surface rain, but with relatively low cloud top height over Indonesian maritime continent (MC). More than 15 years of satellite precipitation data recorded by tropical rainfall measuring mission (TRMM) were used in this analysis. The result reveals a large discrepancy between the active precipitation radar (PR 2A25) and passive microwave imager (TMI 2A12) over land surface. PR identifies low storm top height associated with large downward increase of radar reflectivity. In contrast, TMI identifies large ice scattering associated with higher storm top height, but with lower rain rates near surface. Further investigation identifies larger relative humidity and upward vertical velocity at middle part of the troposphere for the low storm height extremes. This condition represents a larger condensation around 300-500 hPa level, but less for the upper part. As a result, it produces lower amount of ice at the upper troposphere, contrasting to the type of extreme precipitation identified by TMI.

Formation of Nocturnal Offshore Rainfall near the West Coast of Sumatra: Land Breeze or Gravity Wave?

2021 ◽  
Vol 149 (3) ◽  
pp. 715-731
Author(s):  
Hedanqiu Bai ◽  
Gumilang Deranadyan ◽  
Courtney Schumacher ◽  
Aaron Funk ◽  
Craig Epifanio ◽  
...  
Keyword(s):  
West Coast ◽  
Large Scale ◽  
Deep Convection ◽  
Propagation Speed ◽  
Early Morning ◽  
Land Breeze ◽  
Maritime Continent ◽  
The West ◽  
Rainfall Events ◽  
Low Level

AbstractAfternoon deep convection over the Maritime Continent islands propagates offshore in the evening to early morning hours, leading to a nocturnal rainfall maximum over the nearby ocean. This work investigates the formation of the seaward precipitation migration off western Sumatra and its intraseasonal and seasonal characteristics using BMKG C-band radar observations from Padang and ERA5 reanalysis. A total of 117 nocturnal offshore rainfall events were identified in 2018, with an average propagation speed of 4.5 m s−1 within 180 km of Sumatra. Most offshore propagation events occur when the Madden–Julian oscillation (MJO) is either weak (real-time multivariate MJO index < 1) or active over the Indian Ocean (phases 1–3), whereas very few occur when the MJO is active over the Maritime Continent and western Pacific Ocean (phases 4–6). The occurrence of offshore rainfall events also varies on the basis of the seasonal evolution of the large-scale circulation associated with the Asian–Australian monsoons, with fewer events during the monsoon seasons of December–February and June–August and more during the transition seasons of March–May and September–November. Low-level convergence, resulting from the interaction of the land breeze and background low-level westerlies, is found to be the primary driver for producing offshore convective rain propagation from the west coast of Sumatra. Stratiform rain propagation speeds are further increased by upper-level easterlies, which explains the faster migration speed of high reflective clouds observed by satellite. However, temperature anomalies associated with daytime convective latent heating over Sumatra indicate that gravity waves may also modulate the offshore environment to be conducive to seaward convection migration.

scholarly journals The Precipitation Characteristics of ISCCP Tropical Weather States

2013 ◽  
Vol 26 (3) ◽  
pp. 772-788 ◽  
Author(s):  
Dongmin Lee ◽  
Lazaros Oreopoulos ◽  
George J. Huffman ◽  
William B. Rossow ◽  
In-Sik Kang
Keyword(s):  
Large Scale ◽  
Tropical Rainfall Measuring Mission ◽  
Global Precipitation Climatology Project ◽  
Surface Precipitation ◽  
Daily Data ◽  
Precipitation Characteristics ◽  
Dominant State ◽  
Tropical Weather ◽  
Tropical Hydrology ◽  
Global Precipitation

Abstract The authors examine the daytime precipitation characteristics of the International Satellite Cloud Climatology Project (ISCCP) weather states in the extended tropics (35°S–35°N) for a 10-yr period. The main precipitation dataset used is the Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis operational product 3B42 dataset, but Global Precipitation Climatology Project daily data are also used for comparison. It is found that the most convectively active ISCCP weather state (WS1), despite an occurrence frequency below 10%, is the most dominant state with regard to surface precipitation, producing both the largest mean precipitation rates when present and the largest percent contribution to the total precipitation of the tropics; yet, even this weather state appears to not precipitate about half the time, although this may be to some extent an artifact of detection and spatiotemporal matching limitations of the precipitation dataset. WS1 exhibits a modest annual cycle of the domain-average precipitation rate, but notable seasonal shifts in its geographic distribution. The precipitation rates of the other weather states appear to be stronger when occurring before or after WS1. The precipitation rates of the various weather states are different between ocean and land, with WS1 producing higher daytime rates on average over ocean than land, likely because of the larger size and more persistent nature of oceanic WS1s. The results of this study, in addition to advancing the understanding of tropical hydrology, can serve as higher-order diagnostics for evaluating the realism of tropical precipitation distributions in large-scale models.

scholarly journals Constraints on Cumulus Parameterization from Simulations of Observed MJO Events

2015 ◽  
Vol 28 (16) ◽  
pp. 6419-6442 ◽  
Author(s):  
Anthony D. Del Genio ◽  
Jingbo Wu ◽  
Audrey B. Wolf ◽  
Yonghua Chen ◽  
Mao-Sung Yao ◽  
...  
Keyword(s):  
General Circulation ◽  
Large Scale ◽  
Deep Convection ◽  
Circulation Model ◽  
Longwave Radiation ◽  
Tropical Rainfall Measuring Mission ◽  
Cumulus Parameterization ◽  
Cold Pools ◽  
Atmospheric Radiation Measurement ◽  
Goddard Institute

Abstract Two recent activities offer an opportunity to test general circulation model (GCM) convection and its interaction with large-scale dynamics for observed Madden–Julian oscillation (MJO) events. This study evaluates the sensitivity of the Goddard Institute for Space Studies (GISS) GCM to entrainment, rain evaporation, downdrafts, and cold pools. Single Column Model versions that restrict weakly entraining convection produce the most realistic dependence of convection depth on column water vapor (CWV) during the Atmospheric Radiation Measurement MJO Investigation Experiment at Gan Island. Differences among models are primarily at intermediate CWV where the transition from shallow to deeper convection occurs. GCM 20-day hindcasts during the Year of Tropical Convection that best capture the shallow–deep transition also produce strong MJOs, with significant predictability compared to Tropical Rainfall Measuring Mission data. The dry anomaly east of the disturbance on hindcast day 1 is a good predictor of MJO onset and evolution. Initial CWV there is near the shallow–deep transition point, implicating premature onset of deep convection as a predictor of a poor MJO simulation. Convection weakly moistens the dry region in good MJO simulations in the first week; weakening of large-scale subsidence over this time may also affect MJO onset. Longwave radiation anomalies are weakest in the worst model version, consistent with previous analyses of cloud/moisture greenhouse enhancement as the primary MJO energy source. The authors’ results suggest that both cloud-/moisture-radiative interactions and convection–moisture sensitivity are required to produce a successful MJO simulation.

Residual Diagnosis of Diabatic Heating from ERA-40 and NCEP Reanalyses: Intercomparisons with TRMM

2009 ◽  
Vol 22 (2) ◽  
pp. 414-428 ◽  
Author(s):  
Steven C. Chan ◽  
Sumant Nigam
Keyword(s):  
Large Scale ◽  
Diabatic Heating ◽  
Tropical Rainfall Measuring Mission ◽  
Latent Heating ◽  
Maritime Continent ◽  
Precipitation Estimates ◽  
Trmm Precipitation ◽  
Heating Profiles ◽  
The Tropics ◽  
Heating Profile

Abstract Diabatic heating is diagnosed from the 40-yr ECMWF Re-Analysis (ERA-40) circulation as a residue in the thermodynamic equation. The heating distribution is compared with the heating structure diagnosed from NCEP and 15-yr ECMWF Re-Analysis (ERA-15) circulation and latent heating generated from Tropical Rainfall Measuring Mission (TRMM) observations using the convective–stratiform heating (CSH) algorithm. The ERA-40 residual heating in the tropics is found to be stronger than NCEP’s (and ERA-15), especially in July when its zonal–vertical average is twice as large. The bias is strongest over the Maritime Continent in January and over the eastern basins and Africa in July. Comparisons with precipitation indicate ERA-40 heating to be much more realistic over the eastern Pacific but excessive over the Maritime Continent, by at least 20% in January. Intercomparison of precipitation estimates from heating-profile integrals and station and satellite analyses reveals the TRMM CSH latent heating to be chronically weak by as much as a factor of 2! It is the low-side outlier among nine precipitation estimates in three of the four analyzed regions. No less worrisome is the inconsistency between the integral of the CSH latent heating profile in the tropics and the TRMM precipitation retrievals constraining the CSH algorithm (e.g., the 3A25 analysis). Confronting TRMM’s diagnosis of latent heating from local rainfall retrievals and local cumulus-model heating profiles with heating based on the large-scale assimilated circulation is a defining attribute of this study.

scholarly journals Equatorial Waves Including the Madden–Julian Oscillation in TRMM Rainfall and OLR Data

2004 ◽  
Vol 17 (22) ◽  
pp. 4387-4406 ◽  
Author(s):  
Hye-Kyung Cho ◽  
Kenneth P. Bowman ◽  
Gerald R. North
Keyword(s):  
Large Scale ◽  
Longwave Radiation ◽  
Tropical Rainfall Measuring Mission ◽  
Space Time ◽  
Madden Julian Oscillation ◽  
Limited Sampling ◽  
The Tropics ◽  
The Waves ◽  
Section Analysis ◽  
Equatorial Rossby Waves

Abstract Four years of outgoing longwave radiation (OLR) and rainfall data from the Tropical Rainfall Measuring Mission (TRMM) are investigated to find the dominant large-scale wave modes in the Tropics. By using space– time cross-section analysis and spectral analysis, the longitudinal and latitudinal behaviors of the overall waves and the dominant waves are observed. Despite the noisy nature of precipitation data and the limited sampling by the TRMM satellite, pronounced peaks are found for Kelvin waves, n = 1 equatorial Rossby waves (ER), and mixed Rossby–gravity waves (MRG). Madden–Julian oscillation (MJO) and tropical depression (TD)-type disturbances are also detected. The seasonal evolution of these waves is investigated. An appendix includes a study of sampling and aliasing errors due to the peculiar space–time sampling pattern of TRMM. It is shown that the waves detected in this study are not artifacts of these sampling features. The results presented here are compared with previous studies. Consistency with their results gives confidence in the TRMM data for wave studies. The results from this study can be utilized for modeling and testing theories. Also, it may be useful for the future users of the TRMM data to understand the nature of the TRMM satellite sampling.

scholarly journals RESPON CURAH HUJAN DIURNAL TERHADAP MADDEN-JULIAN OSCILLATION AKTIF DI BENUA MARITIM BERBASIS GSMAP GAUGE-CALIBRATED V7

2021 ◽  
Vol 22 (1) ◽  
pp. 17-24
Author(s):  
Achmad Fahruddin Rais ◽  
Ahmad Kosasih ◽  
Soenardi ◽  
Yamin Saleh Saidu ◽  
Sanya Gautami ◽  
...  
Keyword(s):  
Phase Shift ◽  
Outgoing Longwave Radiation ◽  
Longwave Radiation ◽  
Madden Julian Oscillation ◽  
Maritime Continent ◽  
June July August ◽  
Diurnal Rainfall ◽  
The Mean ◽  
June July ◽  
Peak Phase

Intisari Keberadaan pergeseran puncak curah hujan diurnal (DR) terhadap Madden-Julian Oscillation (MJO) aktif di Maritime Continent (MC) masih diperdebatkan sehingga studi ini bertujuan untuk menginvestigasi perubahan tersebut. Selain itu, intensitas rata-rata dan amplitudo DR juga dikaji dalam penelitian ini berbasis GSMaP Gauge-Calibrated V7. Komposit anomali intensitas rata-rata (Ra), amplitudo (Rax) DR MJO aktif dan perbandingan fase puncak DR MJO aktif terhadap klimatologinya (Pax-Pm) pada periode Desember-Januari-Februari (DJF), Maret-April-Mei (MAM), Juni-Juli-Agustus (JJA) dan September-Oktober-November (SON) digunakan dalam tulisan ini dengan uji-z 80%. MJO aktif berbasis rekonstruksi outgoing longwave radiation (OLR) dari kedua indeks realtime multivariate MJO (RMM). Hasil memperlihatkan bahwa MJO aktif memodulasi peningkatan intensitas rata-rata dan amplitudo DR di lautan dan mempengaruhi pergeseran puncak DR menjadi lebih cepat 1 jam dari klimatologi musimannya. Abstract The occurrence of peak phase shift of diurnal rainfall (DR) to active Madden-Jullian Oscillation (MJO) has been debatable, so this study is aimed to investigate the change. Moreover, the mean and amplitude intensity of DR were also analyzed in this study based on GSMaP Gauge-Calibrated V7. The composite of the mean (Ra) and amplitude (Rax) intensity anomaly of DR, and the comparison of DR peak phase during the active MJO to its climatology (Pax-Pm) in the period December-January-February (DJF), March-April-May (MAM), June-July-August (JJA), and September-October-November (SON) were used in the study with the z-test of 80%. The active MJO was based on reconstructed outgoing longwave radiation (OLR) of two real-time multivariate MJO (RMM) indexes. The results showed that active MJO modulated the increased mean and amplitude intensity of DR over the ocean and influenced the DR peak phase shift to be faster than its seasonal climatology by one hour.

Sign in / Sign up

Export Citation Format

Share Document