On the Land–Ocean Contrast of Tropical Convection and Microphysics Statistics Derived from TRMM Satellite Signals and Global Storm-Resolving Models

Abstract A 14-yr climatology of Tropical Rainfall Measuring Mission (TRMM) collocated multisensor signal statistics reveals a distinct land–ocean contrast as well as geographical variability of precipitation type, intensity, and microphysics. Microphysics information inferred from the TRMM Precipitation Radar and Microwave Imager show a large land–ocean contrast for the deep category, suggesting continental convective vigor. Over land, TRMM shows higher echo-top heights and larger maximum echoes, suggesting taller storms and more intense precipitation, as well as larger microwave scattering, suggesting the presence of more/larger frozen convective hydrometeors. This strong land–ocean contrast in deep convection is invariant over seasonal and multiyear time scales. Consequently, relatively short-term simulations from two global storm-resolving models can be evaluated in terms of their land–ocean statistics using the TRMM Triple-Sensor Three-Step Evaluation Framework via a satellite simulator. The models evaluated are the NASA Multiscale Modeling Framework (MMF) and the Nonhydrostatic Icosahedral Cloud Atmospheric Model (NICAM). While both simulations can represent convective land–ocean contrasts in warm precipitation to some extent, near-surface conditions over land are relatively moister in NICAM than MMF, which appears to be the key driver in the divergent warm precipitation results between the two models. Both the MMF and NICAM produced similar frequencies of large CAPE between land and ocean. The dry MMF boundary layer enhanced microwave scattering signals over land, but only NICAM had an enhanced deep convection frequency over land. Neither model could reproduce a realistic land–ocean contrast in deep convective precipitation microphysics. A realistic contrast between land and ocean remains an issue in global storm-resolving modeling.

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Effect of Convective Entrainment/Detrainment on the Simulation of the Tropical Precipitation Diurnal Cycle*

Monthly Weather Review ◽

10.1175/mwr3308.1 ◽

2007 ◽

Vol 135 (2) ◽

pp. 567-585 ◽

Cited By ~ 106

Author(s):

Yuqing Wang ◽

Li Zhou ◽

Kevin Hamilton

Keyword(s):

Diurnal Cycle ◽

Deep Convection ◽

Tropical Rainfall Measuring Mission ◽

Atmospheric Model ◽

Convective Precipitation ◽

Shallow Convection ◽

Eddy Simulation ◽

Mature Phase ◽

Diurnal Range ◽

Convective Parameterization Scheme

Abstract A regional atmospheric model (RegCM) developed at the International Pacific Research Center (IPRC) is used to investigate the effect of assumed fractional convective entrainment/detrainment rates in the Tiedtke mass flux convective parameterization scheme on the simulated diurnal cycle of precipitation over the Maritime Continent region. Results are compared with observations based on 7 yr of the Tropical Rainfall Measuring Mission (TRMM) satellite measurements. In a control experiment with the default fractional convective entrainment/detrainment rates, the model produces results typical of most other current regional and global atmospheric models, namely a diurnal cycle with precipitation rates over land that peak too early in the day and with an unrealistically large diurnal range. Two sensitivity experiments were conducted in which the fractional entrainment/detrainment rates were increased in the deep and shallow convection parameterizations, respectively. Both of these modifications slightly delay the time of the rainfall-rate peak during the day and reduce the diurnal amplitude of precipitation, thus improving the simulation of precipitation diurnal cycle to some degree, but better results are obtained when the assumed entrainment/detrainment rates for shallow convection are increased to the value consistent with the published results from a large eddy simulation (LES) study. It is shown that increasing the entrainment/detrainment rates would prolong the development and reduce the strength of deep convection, thus delaying the mature phase and reducing the amplitude of the convective precipitation diurnal cycle over the land. In addition to the improvement in the simulation of the precipitation diurnal cycle, convective entrainment/detrainment rates also affect the simulation of temporal variability of daily mean precipitation and the partitioning of stratiform and convective rainfall in the model. The simulation of the observed offshore migration of the diurnal signal is realistic in some regions but is poor in some other regions. This discrepancy seems not to be related to the convective lateral entrainment/detrainment rate but could be due to the insufficient model resolution used in this study that is too coarse to resolve the complex land–sea contrast.

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Convective response to large-scale forcing in the Tropical Western Pacific simulated by spCAM5 and CanAM4.3

10.5194/gmd-2018-190 ◽

2018 ◽

Author(s):

Toni Mitovski ◽

Jason N. S. Cole ◽

Norman A. McFarlane ◽

Knut von Salzen ◽

Guang J. Zhang

Keyword(s):

Large Scale ◽

Convective Available Potential Energy ◽

Atmospheric Model ◽

Western Pacific ◽

Convective Precipitation ◽

Near Surface ◽

Tropical Western Pacific ◽

Community Atmosphere Model ◽

Hourly Output ◽

Precipitation Events

Abstract. Changes in the large-scale environment during convective precipitation events in the Tropical Western Pacific simulated by version 4.3 of the Canadian Atmospheric Model (CanAM4.3) is compared against those simulated by version 5.0 of the super parameterized Community Atmosphere Model (spCAM5). This is done by compositing sub-hourly output of convective rainfall, convective available potential energy (CAPE), CAPE generation due to large-scale forcing in the free troposphere (dCAPELSFT), and near surface vertical velocity (ω) over the time period May–July 1997. Compared to spCAM5, CanAM4.3 tends to produce more frequent light convective precipitation ( 2 mm h−1). In spCAM5 5 % of convective precipitation events lasted less than 1.5 h and 75 % lasted between 1.5 and 3.0 h while in CanAM4.3 80 % of the events lasted less than 1.5 h. Convective precipitation in spCAM5 is found to be a function of dCAPELSFT and the large-scale near surface ω with variations in ω slightly leading variations in convective precipitation. Convective precipitation in CanAM4.3 does not have the same dependency and instead is found to be a function of CAPE.

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Convective response to large-scale forcing in the tropical western Pacific simulated by spCAM5 and CanAM4.3

Geoscientific Model Development ◽

10.5194/gmd-12-2107-2019 ◽

2019 ◽

Vol 12 (5) ◽

pp. 2107-2117 ◽

Cited By ~ 1

Author(s):

Toni Mitovski ◽

Jason N. S. Cole ◽

Norman A. McFarlane ◽

Knut von Salzen ◽

Guang J. Zhang

Keyword(s):

Large Scale ◽

Convective Available Potential Energy ◽

Atmospheric Model ◽

Western Pacific ◽

Convective Precipitation ◽

Near Surface ◽

Tropical Western Pacific ◽

Community Atmosphere Model ◽

Hourly Output ◽

Precipitation Events

Abstract. Changes in the large-scale environment during convective precipitation events in the tropical western Pacific simulated by version 4.3 of the Canadian Atmospheric Model (CanAM4.3) are compared against those simulated by version 5.0 of the super-parameterized Community Atmosphere Model (spCAM5). This is done by compositing sub-hourly output of convective rainfall, convective available potential energy (CAPE), CAPE generation due to large-scale forcing in the free troposphere (dCAPELSFT) and near-surface vertical velocity (ω) over the time period May–July 1997. Compared to spCAM5, CanAM4.3 tends to produce more frequent light convective precipitation (<0.2 mm h−1) and underestimates the frequency of extreme convective precipitation (>2 mm h−1). In spCAM5, 5 % of convective precipitation events lasted less than 1.5 h and 75 % lasted between 1.5 and 3.0 h, while in CanAM4.3 80 % of the events lasted less than 1.5 h. Convective precipitation in spCAM5 is found to be a function of dCAPELSFT and the large-scale near-surface ω with variations in ω slightly leading variations in convective precipitation. Convective precipitation in CanAM4.3 does not have the same dependency and instead is found to be a function of CAPE.

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A Comparison of TRMM Microwave Techniques for Detecting the Diurnal Rainfall Cycle

Journal of Hydrometeorology ◽

10.1175/jhm507.1 ◽

2006 ◽

Vol 7 (4) ◽

pp. 687-704 ◽

Cited By ~ 17

Author(s):

Victoria L. Sanderson ◽

Chris Kidd ◽

Glenn R. McGregor

Keyword(s):

Tropical Rainfall Measuring Mission ◽

Time Of Day ◽

Precipitation Radar ◽

Near Surface ◽

Diurnal Rainfall ◽

Microwave Imager ◽

Microwave Techniques ◽

Trmm Microwave Imager ◽

Rain Rates ◽

Climatic Signals

Abstract This paper uses rainfall estimates retrieved from active and passive microwave data to investigate how spatially and temporally dependent algorithm biases affect the monitoring of the diurnal rainfall cycle. Microwave estimates used in this study are from the Tropical Rainfall Measuring Mission (TRMM) and include the precipitation radar (PR) near-surface (2A25), Goddard Profiling (GPROF) (2A12), and PR–TRMM Microwave Imager (TMI) (2B31) rain rates from the version 5 (v5) 3G68 product. A rainfall maximum is observed early evening over land, while oceans generally show a minimum in rainfall during the morning. Comparisons of annual and seasonal mean hourly rain rates and harmonics at both global and regional scales show significant differences between the algorithms. Relative and absolute biases over land vary according to the time of day. Clearly, these retrieval biases need accounting for, either in the physics of the algorithm or through the provision of accurate error estimates, to avoid erroneous climatic signals and the discrediting of satellite rainfall estimations.

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

10.31227/osf.io/rhaz4 ◽

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.

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Long-Term Simulations of Thermally Driven Flows and Orographic Convection at Convection-Parameterizing and Cloud-Resolving Resolutions

Journal of Applied Meteorology and Climatology ◽

10.1175/jamc-d-12-0167.1 ◽

2013 ◽

Vol 52 (6) ◽

pp. 1490-1510 ◽

Cited By ~ 43

Author(s):

Wolfgang Langhans ◽

Juerg Schmidli ◽

Oliver Fuhrer ◽

Susanne Bieri ◽

Christoph Schär

Keyword(s):

Deep Convection ◽

Cloud Formation ◽

Convective Precipitation ◽

Small Scale ◽

Large Set ◽

European Alps ◽

Moist Convection ◽

Shallow Convection ◽

Near Surface ◽

Sensitivity Experiments

AbstractThe purpose of this paper is to validate the representation of topographic flows and moist convection over the European Alps in a convection-parameterizing simulation (CPM; Δx = 6.6 km) and two cloud-resolving simulations (CRM; Δx = 1.1 and 2.2 km). All simulations and further sensitivity experiments are validated against a large set of observations for an 18-day fair-weather summer period. The episode considered is characterized by pronounced plain–valley pressure gradients, strong daytime upvalley flows, and weak nighttime down-valley flows. In addition, convective precipitation is recorded during the late afternoon and is preceded by a phase of shallow convection. The observed transition from shallow to deep convection occurs within a 3-h period. The results indicate good agreement between both CRMs and the observed diurnal evolution in terms of near-surface winds, cloud formation, and precipitation. The differences between the two CRMs are surprisingly small. In contrast, the CPM produces too-early peaks of cloud cover and precipitation that are due to a too-early activation of deep convection. Detailed sensitivity experiments show that the convection scheme, rather than the underresolved small-scale topography, is responsible for the poor performance of the CPM. In addition, observations and simulations show that late-morning mass convergence does not correlate with afternoon precipitation. Rather, it is found that enhanced convective activity is related to increased conditional instability.

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Microphysical variability of Amazonian deep convective cores observed by CloudSat and simulated by a multi-scale modeling framework

10.5194/acp-2017-864 ◽

2017 ◽

Cited By ~ 1

Author(s):

J. Brant Dodson ◽

Patrick C. Taylor ◽

Mark Branson

Keyword(s):

Vertical Structure ◽

Deep Convection ◽

Atmospheric Model ◽

Modeling Framework ◽

Multi Scale ◽

Scale Modeling ◽

Model Variant ◽

Single Moment ◽

Double Moment ◽

Reflectivity Data

Abstract. Recently launched cloud-observing satellites provide information about the vertical structure of deep convection and its microphysical characteristics. In this study, CloudSat reflectivity data is stratified by cloud type, and the contoured frequency by altitude diagrams reveal a double-arc structure in deep convective cores (DCCs) above 8 km. This suggests two distinct hydrometeor modes (snow versus hail/graupel) controlling variability in reflectivity profiles. The day-night contrast in the double-arcs is about four times larger than the wet-dry season contrast. Using QuickBeam, the vertical reflectivity structure of DCCs is analysed in two versions of the Superparameterized Community Atmospheric Model (SP-CAM) with single-moment (no graupel) and double-moment (with graupel) microphysics. Double-moment microphysics shows better agreement with observed reflectivity profiles; however, neither model variant captures the double-arc structure. Ultimately, the results show that simulating realistic DCC vertical structure and its variability requires accurate representation of ice microphysics, in particular the hail/graupel modes, though this alone is insufficient.

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The Sensitivity of WRF Daily Summertime Simulations over West Africa to Alternative Parameterizations. Part II: Precipitation

Monthly Weather Review ◽

10.1175/mwr-d-15-0294.1 ◽

2016 ◽

Vol 145 (1) ◽

pp. 215-233 ◽

Cited By ~ 6

Author(s):

Erik Noble ◽

Leonard M. Druyan ◽

Matthew Fulakeza

Keyword(s):

West Africa ◽

Daily Precipitation ◽

Wrf Model ◽

Tropical Rainfall Measuring Mission ◽

Atmospheric Model ◽

Global Precipitation Climatology Project ◽

Spatiotemporal Variability ◽

Convective Precipitation ◽

Convection Scheme ◽

Wide Range

Abstract This paper evaluates the performance of the Weather Research and Forecasting (WRF) Model as a regional atmospheric model over West Africa. It tests WRF’s sensitivity to 64 configurations of alternative parameterizations in a series of 104 twelve-day September simulations during 11 consecutive years, 2000–10. The 64 configurations combine WRF parameterizations of cumulus convection, radiation, surface hydrology, and the PBL. Simulated daily and total precipitation results are validated against Global Precipitation Climatology Project (GPCP) and Tropical Rainfall Measuring Mission (TRMM) data. Particular attention is given to westward-propagating precipitation maxima associated with African easterly waves (AEWs). A wide range of daily precipitation validation scores demonstrates the influence of alternative parameterizations. The best WRF performers achieve time–longitude correlations (against GPCP) of between 0.35 and 0.42 and spatiotemporal variability amplitudes only slightly higher than observed estimates. A parallel simulation by the benchmark Regional Model version 3 achieves a higher correlation (0.52) and realistic spatiotemporal variability amplitudes. The largest favorable impact on WRF precipitation validation is achieved by selecting the Grell–Devenyi convection scheme, resulting in higher correlations against observations than using the Kain–Fritch convection scheme. Other parameterizations have less obvious impacts. Validation statistics for optimized WRF configurations simulating the parallel period during 2000–10 are more favorable for 2005, 2006, and 2008 than for other years. The selection of some of the same WRF configurations as high scorers in both circulation and precipitation validations supports the notion that simulations of West African daily precipitation benefit from skillful simulations of associated AEW vorticity centers and that simulations of AEWs would benefit from skillful simulations of convective precipitation.

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Soil-atmosphere relationships: The Hungarian perspective

Open Geosciences ◽

10.1515/geo-2015-0036 ◽

2015 ◽

Vol 7 (1) ◽

Cited By ~ 2

Author(s):

Ferenc Ács ◽

Kálmán Rajkai ◽

Hajnalka Breuer ◽

Tamás Mona ◽

Ákos Horváth

Keyword(s):

Pannonian Basin ◽

Deep Convection ◽

Cloud Formation ◽

Convective Precipitation ◽

Trace Gas ◽

Spatiotemporal Pattern ◽

Near Surface ◽

Gas Exchanges ◽

Boundary Layer Height ◽

Soil Atmosphere

AbstractThis study discusses scientific contributions analyzing soil-atmosphere relationships. These studies deal with both the biogeophysical and biogeochemical aspects of this relationship, with biogeophysical aspects being in the majority. All of the studies refer either directly or indirectly to the fundamental importance of soil moisture content. Moisture has a basic influence on the spatiotemporal pattern of evapotranspiration, and so 1) on cloud formation and precipitation events by regulating the intensity of convection, and 2) on the trace-gas exchanges in the near-surface atmosphere. Hungarian modeling efforts have highlighted that soils in the Pannonian Basin have region-specific features. Consequently, shallow and deep convection processes are also, to some extent, region-specific, at least in terms of the diurnal change of the planetary boundary layer height and the spatial distribution of convective precipitation. The soil-dependent region-distinctiveness of these two phenomena has been recognized; at the same time the strength of the relationships has not yet been quantified.

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Comparison of Diurnal Variations in Precipitation Systems Observed by TRMM PR, TMI, and VIRS

Journal of Climate ◽

10.1175/2007jcli2079.1 ◽

2008 ◽

Vol 21 (16) ◽

pp. 4011-4028 ◽

Cited By ~ 45

Author(s):

Munehisa K. Yamamoto ◽

Fumie A. Furuzawa ◽

Atsushi Higuchi ◽

Kenji Nakamura

Keyword(s):

Diurnal Variation ◽

Deep Convection ◽

Heavy Rain ◽

Diurnal Variations ◽

Convective Precipitation ◽

Time Shift ◽

Mature Stage ◽

Peak Time ◽

The Tibetan Plateau ◽

Near Surface

Abstract Tropical Rainfall Measuring Mission (TRMM) data during June–August 1998–2003 are used to investigate diurnal variations of rain and cloud systems over the tropics and midlatitudes. The peak time of the coldest minimum brightness temperature derived from the Visible and Infrared Scanner (VIRS) and the maximum rain rate derived from the Precipitation Radar (PR) and the TRMM Microwave Imager (TMI) are compared. Time distributions are generally consistent with previous studies. However, it is found that systematic shifts in peak time relative to each sensor appeared over land, notably over western North America, the Tibetan Plateau, and oceanic regions such as the Gulf of Mexico. The peak time shift among PR, TMI, and VIRS is a few hours. The relationships among the amplitude of diurnal variation, convective frequency, storm height, and rain amount are further investigated and compared to the systematic peak time shifts. The regions where the systematic shift appears correspond to large amplitude of diurnal variation, high convective frequency, and high storm height. Over land and over ocean near the coast, the relationships are rather clear, but not over open ocean. The sensors likely detect different stages in the evolution of convective precipitation, which would explain the time shift. The PR directly detects near-surface rain. The TMI observes deep convection and solid hydrometeors, sensing heavy rain during the mature stage. VIRS detects deep convective clouds in mature and decaying stages. The shift in peak time particularly between PR (TMI) and VIRS varies by region.

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