Causes of large projected increases in hurricane precipitation rates with global warming

Abstract Recent climate modeling studies point to an increase in tropical cyclone rainfall rates in response to climate warming. These studies indicate that the percentage increase in tropical cyclone rainfall rates often outpaces the increase in saturation specific humidity expected from the Clausius-Clapeyron relation (~7% °C−1). We explore the change in tropical cyclone rainfall rates over all oceans under global warming using a high-resolution climate model with the ability to simulate the entire intensity spectrum of tropical cyclones. Consistent with previous results, we find a robust increase of tropical cyclone rainfall rates. The percentage increase for inner-core tropical cyclone rainfall rates in our model is markedly larger than the Clausius-Clapeyron rate. However, when the impact of storm intensity is excluded, the rainfall rate increase shows a much better match with the Clausius-Clapeyron rate, suggesting that the “super Clausius-Clapeyron” scaling of rainfall rates with temperature increase is due to the warming-induced increase of tropical cyclone intensity. The increase of tropical cyclone intensity and environmental water vapor, in combination, explain the tropical cyclone rainfall rate increase under global warming.

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The Impact of Targeted Dropwindsonde Observations on Tropical Cyclone Intensity Forecasts of Four Weak Systems during PREDICT

Monthly Weather Review ◽

10.1175/mwr-d-13-00284.1 ◽

2014 ◽

Vol 142 (8) ◽

pp. 2860-2878 ◽

Cited By ~ 14

Author(s):

Ryan D. Torn

Keyword(s):

Tropical Cyclone ◽

Meridional Wind ◽

Horizontal Wind ◽

Small Subset ◽

Tropical Cyclone Intensity ◽

Ensemble Forecasts ◽

Cyclone Intensity ◽

Intensity Forecast ◽

Tropical Cyclone Intensity Forecasts ◽

The Impact

Abstract The value of assimilating targeted dropwindsonde observations meant to improve tropical cyclone intensity forecasts is evaluated using data collected during the Pre-Depression Investigation of Cloud-Systems in the Tropics (PREDICT) field project and a cycling ensemble Kalman filter. For each of the four initialization times studied, four different sets of Weather Research and Forecasting Model (WRF) ensemble forecasts are produced: one without any dropwindsonde data, one with all dropwindsonde data assimilated, one where a small subset of “targeted” dropwindsondes are identified using the ensemble-based sensitivity method, and a set of randomly selected dropwindsondes. For all four cases, the assimilation of dropwindsondes leads to an improved intensity forecast, with the targeted dropwindsonde experiment recovering at least 80% of the difference between the experiment where all dropwindsondes and no dropwindsondes are assimilated. By contrast, assimilating randomly selected dropwindsondes leads to a smaller impact in three of the four cases. In general, zonal and meridional wind observations at or below 700 hPa have the largest impact on the forecast due to the large sensitivity of the intensity forecast to the horizontal wind components at these levels and relatively large ensemble standard deviation relative to the assumed observation errors.

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Satellite-based monitoring and prediction of tropical cyclone intensity and movement

MAUSAM ◽

10.54302/mausam.v48i2.3965 ◽

2021 ◽

Vol 48 (2) ◽

pp. 157-168

Author(s):

R. R. KELKAR

Keyword(s):

Tropical Cyclone ◽

Tropical Cyclones ◽

Tropical Cyclone Intensity ◽

Intensity Estimation ◽

Cyclone Intensity ◽

Estimation Scheme ◽

Water Vapour Absorption ◽

Upper Level ◽

Absorption Channel ◽

The Impact

ABSTRACT. Capabilities of meteorological satellites have gone a long way in meeting requirements of synoptic analysis and forecasting of tropical cyclones. This paper shows the impact made by the satellite data in the intensity estimation and track prediction of tropical cyclones in the Indian Seas and also reviews the universally applied Dvorak algorithm for performing tropical cyclone intensity analysis. Extensive use of Dvorak's intensity estimation scheme has revealed many of its limitations and elements of subjectivity in the analysis of tropical cyclones over the Arabian Sea and the Bay of Bengal, which, like cyclones in other ocean basins, also exhibit wide structural variability as seen in the satellite imagery. Satellite-based cyclone tracking techniques include: (i) use of satellite-derived mean wind flow, (ii) animation of sequence of satellite images and extrapolation of the apparent motion of the cloud system and (iii) monitoring changes in the upper level moisture patterns in the water vapour absorption channel imagery. Satellite-based techniques on tropical cyclone intensity estimation and track prediction have led to very significant improvement in disaster warning and consequent saving of life and property.

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The Effect of the Ocean Eddy on Tropical Cyclone Intensity

Journal of the Atmospheric Sciences ◽

10.1175/jas4051.1 ◽

2007 ◽

Vol 64 (10) ◽

pp. 3562-3578 ◽

Cited By ~ 105

Author(s):

Chun-Chieh Wu ◽

Chia-Ying Lee ◽

I-I. Lin

Keyword(s):

Tropical Cyclone ◽

Tropical Cyclones ◽

Mixed Layer ◽

Thermal Structure ◽

Critical Role ◽

Strong Mixing ◽

Rapid Intensification ◽

Tropical Cyclone Intensity ◽

Cyclone Intensity ◽

The Impact

Abstract The rapid intensification of Hurricane Katrina followed by the devastation of the U.S. Gulf States highlights the critical role played by an upper-oceanic thermal structure (such as the ocean eddy or Loop Current) in affecting the development of tropical cyclones. In this paper, the impact of the ocean eddy on tropical cyclone intensity is investigated using a simple hurricane–ocean coupled model. Numerical experiments with different oceanic thermal structures are designed to elucidate the responses of tropical cyclones to the ocean eddy and the effects of tropical cyclones on the ocean. This simple model shows that rapid intensification occurs as a storm encounters the ocean eddy because of enhanced heat flux. While strong winds usually cause strong mixing in the mixed layer and thus cool down the sea surface, negative feedback to the storm intensity of this kind is limited by the presence of a warm ocean eddy, which provides an insulating effect against the storm-induced mixing and cooling. Two eddy factors, FEDDY-S and FEDDY-T, are defined to evaluate the effect of the eddy on tropical cyclone intensity. The efficiency of the eddy feedback effect depends on both the oceanic structure and other environmental parameters, including properties of the tropical cyclone. Analysis of the functionality of FEDDY-T shows that the mixed layer depth associated with either the large-scale ocean or the eddy is the most important factor in determining the magnitude of eddy feedback effects. Next to them are the storm’s translation speed and the ambient relative humidity.

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What Has Changed the Proportion of Intense Hurricanes in the Last 30 Years?

Journal of Climate ◽

10.1175/2007jcli1715.1 ◽

2008 ◽

Vol 21 (6) ◽

pp. 1432-1439 ◽

Cited By ~ 39

Author(s):

Liguang Wu ◽

Bin Wang

Keyword(s):

Global Warming ◽

Tropical Cyclone ◽

North Atlantic ◽

North Pacific ◽

Critical Factor ◽

Tropical Cyclone Intensity ◽

Cyclone Intensity ◽

The Past ◽

The North ◽

The North Atlantic

Abstract The recently reported increase in the proportion of intense hurricanes is considerably larger than those projected by the maximum potential intensity (MPI) theory and the results of numerical simulation. To reconcile this discrepancy, the authors examined the best-track datasets for the North Atlantic (NA), western North Pacific (WNP), and eastern North Pacific (ENP) basins. It was found that the changes in the tropical cyclone formation locations and prevailing tracks may have contributed to the changes in the proportion of the intense hurricanes over the past 30 yr. The authors suggest that the changes in the formation locations and prevailing tracks have a profound impact on the basinwide tropical cyclone intensity. Thus, how the atmospheric circulation in the tropical cyclone basins responds to the global warming may be a critical factor in understanding the impacts of global warming on tropical cyclone intensity.

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Cyclone Center: Can Citizen Scientists Improve Tropical Cyclone Intensity Records?

Bulletin of the American Meteorological Society ◽

10.1175/bams-d-13-00152.1 ◽

2015 ◽

Vol 96 (4) ◽

pp. 591-607 ◽

Cited By ~ 22

Author(s):

Christopher C. Hennon ◽

Kenneth R. Knapp ◽

Carl J. Schreck ◽

Scott E. Stevens ◽

James P. Kossin ◽

...

Keyword(s):

Tropical Cyclone ◽

Historical Record ◽

Tropical Cyclone Intensity ◽

Remotely Sensed Data ◽

Cyclone Intensity ◽

Modern Times ◽

Maximum Wind ◽

Recent Climate ◽

The Relationship ◽

Global Reanalysis

Abstract The global tropical cyclone (TC) intensity record, even in modern times, is uncertain because the vast majority of storms are only observed remotely. Forecasters determine the maximum wind speed using a patchwork of sporadic observations and remotely sensed data. A popular tool that aids forecasters is the Dvorak technique—a procedural system that estimates the maximum wind based on cloud features in IR and/or visible satellite imagery. Inherently, the application of the Dvorak procedure is open to subjectivity. Heterogeneities are also introduced into the historical record with the evolution of operational procedures, personnel, and observing platforms. These uncertainties impede our ability to identify the relationship between tropical cyclone intensities and, for example, recent climate change. A global reanalysis of TC intensity using experts is difficult because of the large number of storms. We will show that it is possible to effectively reanalyze the global record using crowdsourcing. Through modifying the Dvorak technique into a series of simple questions that amateurs (“citizen scientists”) can answer on a website, we are working toward developing a new TC dataset that resolves intensity discrepancies in several recent TCs. Preliminary results suggest that the performance of human classifiers in some cases exceeds that of an automated Dvorak technique applied to the same data for times when the storm is transitioning into a hurricane.

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Simulated Changes in Tropical Cyclone Size, Accumulated Cyclone Energy and Power Dissipation Index in a Warmer Climate

Oceans ◽

10.3390/oceans2040039 ◽

2021 ◽

Vol 2 (4) ◽

pp. 688-699

Author(s):

Michael Wehner

Keyword(s):

Tropical Cyclone ◽

Power Dissipation ◽

General Circulation ◽

Circulation Model ◽

Global Changes ◽

Tropical Cyclone Intensity ◽

Cyclone Intensity ◽

Storm Frequency ◽

Index Changes ◽

The Impact

Detection, attribution and projection of changes in tropical cyclone intensity statistics are made difficult from the potentially decreasing overall storm frequency combined with increases in the peak winds of the most intense storms as the climate warms. Multi-decadal simulations of stabilized climate scenarios from a high-resolution tropical cyclone permitting atmospheric general circulation model are used to examine simulated global changes from warmer temperatures, if any, in estimates of tropical cyclone size, accumulated cyclonic energy and power dissipation index. Changes in these metrics are found to be complicated functions of storm categorization and global averages of them are unlikely to easily reveal the impact of climate change on future tropical cyclone intensity statistics.

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