scholarly journals Tropical Cyclone–Induced Upper-Ocean Mixing and Climate: Application to Equable Climates

2008 ◽  
Vol 21 (4) ◽  
pp. 638-654 ◽  
Author(s):  
Robert L. Korty ◽  
Kerry A. Emanuel ◽  
Jeffery R. Scott
Keyword(s):  
Carbon Dioxide ◽  
Heat Flux ◽  
Surface Water ◽  
Tropical Cyclone ◽  
Dynamic Response ◽  
Tropical Cyclones ◽  
Climate Changes ◽  
Tropical Oceans ◽  
Warm Surface Water ◽  
Upper Ocean Mixing

Abstract Tropical cyclones instigate an isolated blast of vigorous mixing in the upper tropical oceans, stirring warm surface water with cooler water in the thermocline. Previous work suggests that the frequency, intensity, and lifetime of these storms may be functions of the climate state, implying that transient tropical mixing could have been stronger during warmer equable climates with higher concentrations of carbon dioxide. Stronger mixing of the tropical oceans can force the oceans’ meridional heat flux to increase, cooling tropical latitudes while warming higher ones. This response differs significantly from previous modeling studies of equable climates that used static mixing; coupling mixing to climate changes the dynamic response. A parameterization of mixing from tropical cyclones is developed, and including it leads to a cooling of tropical oceans and a warming of subtropical waters compared with control cases with fixed mixing. The mixing penetration depth regulates the magnitude of the response.

scholarly journals Application of Airborne Passive Microwave Observations for Monitoring Inland Flooding Caused by Tropical Cyclones

2009 ◽  
Vol 26 (10) ◽  
pp. 2051-2070
Author(s):  
Courtney D. Buckley ◽  
Robbie E. Hood ◽  
Frank J. LaFontaine
Keyword(s):  
United States ◽  
Surface Water ◽  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
Field Experiments ◽  
Vegetation Indices ◽  
The United States ◽  
Unmanned Aircraft ◽  
Passive Microwave ◽  
Inland Flooding

Abstract Inland flooding from tropical cyclones is a significant factor in storm-related deaths in the United States and other countries, with the majority of tropical cyclone fatalities recorded in the United States resulting from freshwater flooding. Information collected during National Aeronautics and Space Administration (NASA) tropical cyclone field experiments suggests that surface water and flooding can be detected and therefore monitored at a greater spatial resolution by using passive microwave airborne radiometers than by using satellite sensors. The 10.7-GHz frequency of the NASA Advanced Microwave Precipitation Radiometer (AMPR) has demonstrated high-resolution detection of anomalous surface water and flooding in numerous situations. In this study, an analysis of three cases is conducted utilizing satellite and airborne radiometer data. Data from the 1998 Third Convection and Moisture Experiment (CAMEX-3) are utilized to detect surface water during the landfalling Hurricane Georges in both the Dominican Republic and Louisiana. Another case studied was the landfalling Tropical Storm Gert in eastern Mexico during the Tropical Cloud Systems and Processes (TCSP) experiment in 2005. AMPR data are compared to topographic data and vegetation indices to evaluate the significance of the surface water signature visible in the 10.7-GHz information. The results illustrate the AMPR’s utility in monitoring surface water that current satellite-based passive microwave radiometers are unable to monitor because of their coarser resolutions. This suggests the benefit of a radiometer with observing frequencies less than 11 GHz deployed on a manned aircraft or unmanned aircraft system to provide early detection in real time of expanding surface water or flooding conditions.

A Comparison between Moist and Dry Tropical Cyclones: The Low Effectiveness of Surface Sensible Heat Flux in Storm Intensification

2021 ◽  
Author(s):  
Zhanhong Ma ◽  
Jianfang Fei
Keyword(s):  
Heat Flux ◽  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
Potential Temperature ◽  
Sensible Heat Flux ◽  
Equivalent Potential Temperature ◽  
Sensible Heat ◽  
Budget Analysis ◽  
Equivalent Potential ◽  
Surface Sensible Heat Flux

AbstractRecent numerical modeling studies demonstrate that dry tropical cyclones can be stably sustained via supply of surface sensible heat flux. This raises questions of whether surface sensible heat flux (SHX) and latent heat flux (LHX) have the same effect on the intensity evolution of tropical cyclones. An estimation of equivalent potential temperature budget in the boundary layer shows that LHX leads to larger increase in equivalent potential temperature than SHX even when they possess the same magnitude. By formulating these two kinds of surface heat fluxes with the same mathematical framework, the simulated intensifications of moist and dry tropical cyclones are compared, with the former driven exclusively by LHX and the latter by SHX. Results show significantly larger intensification rates for the tropical cyclone driven by LHX than that by SHX, revealing low effectiveness of SHX in the intensification of tropical cyclones. The diabatic heating in the moist tropical cyclone occurs accompanying the convection, while it is merely pronounced near the surface in the dry tropical cyclone and is decoupled from the dry convection. A new surface pressure tendency equation is proposed, without incorporating implicit pressure tendency term on the right-hand side. The budget analysis indicates that the SHX is less effective than LHX in lowering surface central pressure and therefore in tropical cyclone intensification. A series of sensitivity experiments suggest that the threshold of energy input required for spinning up a tropical cyclone is lower in the form of LHX than that of SHX.

scholarly journals Tropical cyclone genesis across palaeoclimates

2015 ◽  
Vol 11 (1) ◽  
pp. 181-220 ◽  
Author(s):  
J. H. Koh ◽  
C. M. Brierley
Keyword(s):  
Carbon Dioxide ◽  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
Large Scale ◽  
Climate Models ◽  
Tropical Cyclogenesis ◽  
Tropical Cyclone Genesis ◽  
Inter Tropical Convergence Zone ◽  
Potential Index ◽  
Cyclone Genesis

Abstract. Tropical cyclone genesis is investigated for the Pliocene, Last Glacial Maximum (LGM) and the mid-Holocene through analysis of five climate models. The genesis potential index is used to estimate this from large scale atmospheric properties. The mid-Pliocene and LGM characterise periods where carbon dioxide levels were higher and lower than pre-industrial respectively, while the mid-Holocene differed primarily in its orbital configuration. The number of tropical cyclones formed each year is found to be fairly consistent across the various palaeoclimates. Although there is some model uncertainty in the change of global annual tropical cyclone frequency, there are coherent changes in the spatial patterns of tropical cyclogenesis. During the Pliocene and LGM, changes in carbon dioxide led to sea surface temperature changes throughout the tropics, yet the potential intensity of tropical cyclones appears relatively insensitive to these variations. Changes in tropical cyclone genesis during the mid-Holocene are observed to be asymmetric about the Equator: genesis is reduced in the Northern Hemisphere, but enhanced in the Southern Hemisphere. This is clearly driven by the altered seasonal insolation. Nonetheless, the enhanced seasonality may have driven localised effects on tropical cyclone genesis, through changes to the strength of monsoons and shifting of the inter-tropical convergence zone. Trends in future tropical cyclone genesis are neither consistent between the five models studied, nor with the palaeoclimate results. It is not clear why this should be the case.

scholarly journals KARAKTERISTIK DAN DAMPAK SIKLON TROPIS YANG TUMBUH DI SEKITAR WILAYAH INDONESIA

OSEANA ◽  
2018 ◽  
Vol 43 (2) ◽  
pp. 1-12
Author(s):  
Dewi Surinati ◽  
Dwi Ayu Kusuma
Keyword(s):  
Heat Transfer ◽  
Life Cycle ◽  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
Extreme Weather ◽  
Air Pressure ◽  
Tropical Oceans ◽  
It Impacts ◽  
Strong Winds

CHARACTERISTICS AND IMPACTS OF TROPICAL CYCLONES GROWING AROUND INDONESIAN TERRITORY. Tropical cyclone is a cyclonic originates from tropical oceans and driven principally by heat transfer from the ocean. Tropical cyclone is an atmospheric phenomenon characterized by the emergence of low air pressure that triggers the occurrence of strong winds due to the process of heat transfer from the equator to the latitude. This phenomenon can not be prevented, so that it has great potential to impact on the damage in the area it through. Tropical cyclones can be characterized through their life cycle, scale of power and how it impacts in the area it through. The Cempaka and Dahlia tropical cyclone occuring in 2017 greatly influenced territory of Indonesia. The effect of the cyclone causes extreme weather in Indonesia, especially in areas close to where cyclones are formed.

scholarly journals Tropical cyclone simulations over Bangladesh at convection permitting 4.4 km & 1.5 km resolution

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Hamish Steptoe ◽  
Nicholas Henry Savage ◽  
Saeed Sadri ◽  
Kate Salmon ◽  
Zubair Maalick ◽  
...  
Keyword(s):  
Wind Speed ◽  
Tropical Cyclone ◽  
Sea Level ◽  
Tropical Cyclones ◽  
Weather Forecasting ◽  
Sea Level Pressure ◽  
Mean Sea Level ◽  
Level Pressure ◽  
Medium Range ◽  
Gust Speed

AbstractHigh resolution simulations at 4.4 km and 1.5 km resolution have been performed for 12 historical tropical cyclones impacting Bangladesh. We use the European Centre for Medium-Range Weather Forecasting 5th generation Re-Analysis (ERA5) to provide a 9-member ensemble of initial and boundary conditions for the regional configuration of the Met Office Unified Model. The simulations are compared to the original ERA5 data and the International Best Track Archive for Climate Stewardship (IBTrACS) tropical cyclone database for wind speed, gust speed and mean sea-level pressure. The 4.4 km simulations show a typical increase in peak gust speed of 41 to 118 knots relative to ERA5, and a deepening of minimum mean sea-level pressure of up to −27 hPa, relative to ERA5 and IBTrACS data. The downscaled simulations compare more favourably with IBTrACS data than the ERA5 data suggesting tropical cyclone hazards in the ERA5 deterministic output may be underestimated. The dataset is freely available from 10.5281/zenodo.3600201.

scholarly journals Are Special Processes at Work in the Rapid Intensification of Tropical Cyclones?

2015 ◽  
Vol 143 (3) ◽  
pp. 878-882 ◽  
Author(s):  
Roman Kowch ◽  
Kerry Emanuel
Keyword(s):  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
Internal Variability ◽  
Open Ocean ◽  
Rapid Intensification ◽  
Exponential Distributions ◽  
Frequency Distributions ◽  
Fat Tail ◽  
Dissipation Rates ◽  
Special Factors

Abstract Probably not. Frequency distributions of intensification and dissipation developed from synthetic open-ocean tropical cyclone data show no evidence of significant departures from exponential distributions, though there is some evidence for a fat tail of dissipation rates. This suggests that no special factors govern high intensification rates and that tropical cyclone intensification and dissipation are controlled by statistically random environmental and internal variability.

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