scholarly journals Using Satellite Observations to Evaluate the Relationships between Ice Condensate, Latent Heat Release, and Tropical Cyclone Intensification in a Mesoscale Model

2021 ◽  
Vol 149 (1) ◽  
pp. 113-129
Author(s):  
Shun-Nan Wu ◽  
Brian J. Soden ◽  
Yoshiaki Miyamoto ◽  
David S. Nolan ◽  
Stefan A. Buehler
Keyword(s):  
Tropical Cyclone ◽  
Heat Release ◽  
Water Content ◽  
Latent Heat ◽  
Satellite Observations ◽  
Latent Heating ◽  
Latent Heat Release ◽  
Model Simulations ◽  
Ice Water Content ◽  
Ice Water

AbstractThis study examines the relationship between frozen hydrometeors and latent heating in model simulations and evaluates the capability of the Weather Research and Forecasting (WRF) Model to reproduce the observed frozen hydrometeors and their relationship to tropical cyclone (TC) intensification. Previous modeling studies have emphasized the importance of both the amount and location of latent heating in modulating the evolution of TC intensity. However, the lack of observations limits a full understanding of its importance in the real atmosphere. Idealized simulations using WRF indicate that latent heating is strongly correlated to the amount of ice water content, suggesting that ice water content can serve as an observable proxy for latent heat release in the mid- to upper troposphere. Based on this result, satellite observations are used to create storm-centered composites of ice water path as a function of TC intensity. The model reasonably captures the vertical and horizontal distribution of ice water content and its dependence upon TC intensity, with differences typically less than 20%. The model also captures the signature of increased ice water content for intensifying TCs, suggesting that observations of ice water content provide a useful diagnostic for understanding and evaluating model simulations of TC intensification.

scholarly journals Signatures of Tropical Cyclone Intensification in Satellite Measurements of Ice and Liquid Water Content

2017 ◽  
Vol 145 (10) ◽  
pp. 4081-4091 ◽  
Author(s):  
Shun-Nan Wu ◽  
Brian J. Soden
Keyword(s):  
Tropical Cyclone ◽  
Water Content ◽  
Liquid Water ◽  
Vertical Profile ◽  
Liquid Water Content ◽  
Intensity Change ◽  
Latent Heating ◽  
Cloud Water Content ◽  
Ice Water Content ◽  
Ice Water

This study examines how the structure and amount of cloud water content are associated with tropical cyclone (TC) intensity change using the CloudSat Tropical Cyclone (CSTC) dataset. Theoretical and modeling studies have demonstrated the importance of both the magnitude and vertical structure of latent heating in regulating TC intensity. However, the direct observations of the latent heat release and its vertical profile are scarce. The CSTC dataset provides the opportunity to infer the vertical profile of the latent heating from CloudSat retrievals of cloud ice water content (IWC) and liquid water content (LWC). It is found that strengthening storms have ~20% higher IWC than weakening storms, especially in the midtroposphere near the eyewall. These differences in IWC exist up to 24 h prior to an intensity change and are observed for all storm categories except major TCs. A similar analysis of satellite-observed rainfall rates indicates that strengthening storms have slightly higher rainfall rates 6 h prior to intensification. However, the rainfall signal is less robust than what is observed for IWC, and disappears for lead times greater than 6 h. Such precursors of TC intensity change provide observationally based metrics that may be useful in constraining model simulations of TC genesis and intensification.

Latent Heating Retrieved from TRMM and GPM Satellite Measurements

2020 ◽  
Author(s):  
Wei-Kuo Tao ◽  
Steve Lang ◽  
Takamichi Iguchi
Keyword(s):  
Heat Release ◽  
Latent Heat ◽  
Tropical Rainfall Measuring Mission ◽  
Phase Changes ◽  
Latent Heating ◽  
Latent Heat Release ◽  
Satellite Measurements ◽  
Space Time Structure ◽  
Global Precipitation Mission ◽  
Global Precipitation

<p>Latent heat release itself is a consequence of phase changes between the vapor, liquid, and frozen states of water.  This paper will highlight the retrieval of latent heat release from satellite measurements generated by the Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Mission (GPM) satellite observatory.  Both TRMM and GPM are providing four-dimensional account of rainfall and its associated precipitation properties over the global Tropics and mid-latitudes: information that can be used to estimate the space-time structure of latent heating.</p><p> </p><p>Goddard Convective-Stratiform or CSH retrieved LH is one of two standard LH products (the other one is from Japan Spectral Latent Heating or SLH). This paper will present (1) the new improvements of the CSH LH algorithm by better CRM simulated LH for its look-up table, and (2) the performance of CSH retrieved LH by comparison with surface rainfall rate.  In addition, the similarities and differences of CSH retrieved LH obtained from TRMM and GPM measurements, respectively, will be presented.  At the end of presentation, the further research on latent heating retrieval from satellites will be discussed.</p>

scholarly journals The Importance of Resolving Mesoscale Latent Heating in the North Atlantic Storm Track

2013 ◽  
Vol 70 (7) ◽  
pp. 2234-2250 ◽  
Author(s):  
Jeff Willison ◽  
Walter A. Robinson ◽  
Gary M. Lackmann
Keyword(s):  
Heat Release ◽  
Latent Heat ◽  
North Atlantic ◽  
General Circulation ◽  
Storm Track ◽  
Latent Heating ◽  
Latent Heat Release ◽  
Grid Spacing ◽  
The North ◽  
The North Atlantic

Abstract Theoretical, observational, and modeling studies have established an important role for latent heating in midlatitude cyclone development. Models simulate some contribution from condensational heating to cyclogenesis, even with relatively coarse grid spacing (on the order of 100 km). Our goal is to more accurately assess the diabatic contribution to storm-track dynamics and cyclogenesis while bridging the gap between climate modeling and synoptic dynamics. This study uses Weather Research and Forecasting model (WRF) simulations with 120- and 20-km grid spacing to demonstrate the importance of resolving additional mesoscale features that are associated with intense precipitation and latent heat release within extratropical cyclones. Sensitivity to resolution is demonstrated first with a case study, followed by analyses of 10 simulated winters over the North Atlantic storm track. Potential vorticity diagnostics are employed to isolate the influences of latent heating on storm dynamics, and terms in the Lorenz energy cycle are analyzed to determine the resulting influences on the storm track. The authors find that the intensities of individual storms and their aggregate behavior in the storm track are strongly sensitive to horizontal resolution. An enhanced positive feedback between cyclone intensification and latent heat release is seen at higher resolution, resulting in a systematic increase in eddy intensity and a stronger storm track relative to the coarser simulations. These results have implications for general circulation models and their projections of climate change.

scholarly journals The role of surface fluxes in the development of a tropical-like cyclone in southern Italy

2008 ◽  
Vol 2 (1) ◽  
pp. 35-39 ◽  
Author(s):  
M. M. Miglietta ◽  
S. Davolio ◽  
A. Moscatello ◽  
F. Pacifico ◽  
R. Rotunno
Keyword(s):  
Tropical Cyclone ◽  
Numerical Simulations ◽  
Heat Release ◽  
Latent Heat ◽  
Initial Phase ◽  
Southern Italy ◽  
Surface Fluxes ◽  
Mature Stage ◽  
Latent Heat Release

Abstract. Numerical simulations of a tropical-like cyclone in southern Italy have been performed with two different modelling systems (BOLAM-MOLOCH and WRF) with the aim of discussing the role of the surface fluxes in the development of the vortex and evaluating their intensity during the mature stage of the cyclone. Although significant differences emerge in their intensity, both the modelling systems agree in showing that the surface fluxes are more important than the latent heat release associated with convection in the initial phase of the vortex lifecycle, while they are less relevant (although more intense) when the minimum assumes the characteristic of a tropical cyclone.

scholarly journals The influence of the coastal front on heavy rainfall events along the east coast

2019 ◽  
Author(s):  
◽  
Chasity B. Henson
Keyword(s):  
Tropical Cyclone ◽  
Heat Release ◽  
Latent Heat ◽  
Heavy Rainfall ◽  
East Coast ◽  
Latent Heat Release ◽  
Rainfall Events ◽  
Upper Level ◽  
Heavy Rainfall Events ◽  
Frontal Boundary

Coastal fronts are commonly found along the East Coast of the United States and can often be associated with intense rainfall and flooding due to elevated convection on the cold side of the boundary. Five heavy rainfall events ([greater to or equal than] 250 mm 24 hr-1) during the fall months along the East Coast were investigated using numerical weather prediction (NWP) models to determine the influence of an upper-level trough/cut-off low, an offshore tropical cyclone, a frontal boundary, and a moisture plume on the intense precipitation. Using experimental NWP simulations, it was determined that the tropical cyclone had an impact on the moisture plume and subsequent location of precipitation due to an associated deformation zone. The tropical cyclone prolonged the events by 6 hours, but inhibited the amount of moisture and resulting precipitation by deterring southeasterly flow. Evaporation from precipitation (surface heat fluxes) contributed to less than 25% (33%) of the precipitation, while latent heat release had the largest impact on the rain totals due to positive feedback from convection and an influence on the frontal boundary. Terrain also impacted the frontal boundary in each event, altering precipitation totals. Parcel trajectories confirmed regions of frontogenesis to be the main source of lift for the release of gravitational instability and convective initiation in each event, while the extratropical cyclone provided upper-level support for ascent and organized the plume of deep tropospheric moisture perpendicular to the front. Three of the five events lasted multiple days due to negative PV advection by the irrotational wind, in response to latent heat release in the region of convection, acting to slow the propagation of the upper-level low.

scholarly journals Assimilating remotely sensed cloud optical thickness into a mesoscale model

2011 ◽  
Vol 11 (19) ◽  
pp. 10269-10281
Author(s):  
D. Lauwaet ◽  
K. De Ridder ◽  
P. Pandey
Keyword(s):  
Water Content ◽  
Optical Thickness ◽  
Prediction System ◽  
Model Simulations ◽  
Advanced Regional Prediction System ◽  
Air Temperatures ◽  
Regional Prediction ◽  
Ice Water Content ◽  
Cloud Optical Thickness ◽  
Ice Water

Abstract. The Advanced Regional Prediction System, a mesoscale atmospheric model, is applied to simulate the month of June 2006 with a focus on the near surface air temperatures around Paris. To improve the simulated temperatures which show errors up to 10 K during a day on which a cold front passed Paris, a data assimilation procedure to calculate 3-D analysis fields of specific cloud liquid and ice water content is presented. The method is based on the assimilation of observed cloud optical thickness fields into the Advanced Regional Prediction System model and operates on 1-D vertical columns, assuming that the horizontal background error covariance is infinite, i.e. an independent pixel approximation. The rationale behind it is to find vertical profiles of cloud liquid and ice water content that yield the observed cloud optical thickness values and are consistent with the simulated profile. Afterwards, a latent heat adjustment is applied to the temperature in the vertical column. Data from several meteorological stations in the study area are used to verify the model simulations. The results show that the presented assimilation procedure is able to improve the simulated 2 m air temperatures and incoming shortwave radiation significantly during cloudy days. The scheme is able to alter the position of the cloud fields significantly and brings the simulated cloud pattern closer to the observations. As the scheme is rather simple and computationally inexpensive, it is a promising new technique to improve the surface fields of retrospective model simulations for variables that are affected by the position of the clouds.

scholarly journals Assimilating remotely sensed cloud optical thickness into a mesoscale model

2011 ◽  
Vol 11 (5) ◽  
pp. 13355-13380 ◽  
Author(s):  
D. Lauwaet ◽  
K. De Ridder ◽  
P. Pandey
Keyword(s):  
Water Content ◽  
Optical Thickness ◽  
Prediction System ◽  
Model Simulations ◽  
Advanced Regional Prediction System ◽  
Air Temperatures ◽  
Regional Prediction ◽  
Ice Water Content ◽  
Cloud Optical Thickness ◽  
Ice Water

Abstract. The Advanced Regional Prediction System, a mesoscale atmospheric model, is applied to simulate the month of June 2006 with a focus on the near surface air temperatures around Paris. To improve the simulated temperatures which show errors up to 10 K during a day on which a cold front passed Paris, a data assimilation procedure to calculate 3-D analysis fields of specific cloud liquid and ice water content is presented. The method is based on the assimilation of observed cloud optical thickness fields into the Advanced Regional Prediction System model and operates on 1-D vertical columns, assuming that there is no horizontal background error covariance. The rationale behind it is to find vertical profiles of cloud liquid and ice water content that yield the observed cloud optical thickness values and are consistent with the simulated profile. Afterwards, a latent heat adjustment is applied to the temperature in the vertical column. Data from 4 meteorological surface stations around Paris are used to verify the model simulations. The results show that the presented assimilation procedure is able to improve the simulated 2 m air temperatures and incoming shortwave radiation significantly during cloudy days. The scheme is able to alter the position of the cloud fields significantly and brings the simulated cloud pattern closer to the observations. As the scheme is rather simple and computationally fast, it is a promising new technique to improve the surface fields of retrospective model simulations for variables that are affected by the position of the clouds.

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