scholarly journals A new perspective on MST radar observations of stratospheric intrusions into-troposphere associated with tropical cyclone

2009 ◽  
Vol 36 (15) ◽  
pp. n/a-n/a ◽  
Author(s):  
Siddarth Shankar Das
Keyword(s):  
Tropical Cyclone ◽  
Radar Observations ◽  
Mst Radar ◽  
New Perspective ◽  
Stratospheric Intrusions

MST radar observations of short-period gravity wave during overhead tropical cyclone

Radio Science ◽  
2012 ◽  
Vol 47 (2) ◽  
pp. n/a-n/a ◽  
Author(s):  
Siddarth Shankar Das ◽  
K. N. Uma ◽  
Subrata Kumar Das
Keyword(s):  
Tropical Cyclone ◽  
Gravity Wave ◽  
Radar Observations ◽  
Short Period ◽  
Mst Radar

On the Hyperbolicity of the Bulk Air–Sea Heat Flux Functions: Insights into the Efficiency of Air–Sea Moisture Disequilibrium for Tropical Cyclone Intensification

2021 ◽  
Vol 149 (5) ◽  
pp. 1517-1534
Author(s):  
Benjamin Jaimes de la Cruz ◽  
Lynn K. Shay ◽  
Joshua B. Wadler ◽  
Johna E. Rudzin
Keyword(s):  
Tropical Cyclone ◽  
Surface Wind ◽  
Heat Content ◽  
Surface Heat ◽  
Heat Fluxes ◽  
Ocean Heat Uptake ◽  
Surface Heat Fluxes ◽  
Heat Uptake ◽  
Moisture Fluxes ◽  
New Perspective

AbstractSea-to-air heat fluxes are the energy source for tropical cyclone (TC) development and maintenance. In the bulk aerodynamic formulas, these fluxes are a function of surface wind speed U10 and air–sea temperature and moisture disequilibrium (ΔT and Δq, respectively). Although many studies have explained TC intensification through the mutual dependence between increasing U10 and increasing sea-to-air heat fluxes, recent studies have found that TC intensification can occur through deep convective vortex structures that obtain their local buoyancy from sea-to-air moisture fluxes, even under conditions of relatively low wind. Herein, a new perspective on the bulk aerodynamic formulas is introduced to evaluate the relative contribution of wind-driven (U10) and thermodynamically driven (ΔT and Δq) ocean heat uptake. Previously unnoticed salient properties of these formulas, reported here, are as follows: 1) these functions are hyperbolic and 2) increasing Δq is an efficient mechanism for enhancing the fluxes. This new perspective was used to investigate surface heat fluxes in six TCs during phases of steady-state intensity (SS), slow intensification (SI), and rapid intensification (RI). A capping of wind-driven heat uptake was found during periods of SS, SI, and RI. Compensation by larger values of Δq > 5 g kg−1 at moderate values of U10 led to intense inner-core moisture fluxes of greater than 600 W m−2 during RI. Peak values in Δq preferentially occurred over oceanic regimes with higher sea surface temperature (SST) and upper-ocean heat content. Thus, increasing SST and Δq is a very effective way to increase surface heat fluxes—this can easily be achieved as a TC moves over deeper warm oceanic regimes.

Deduction of temperature profile from MST radar observations of vertical wind

1996 ◽  
Vol 23 (3) ◽  
pp. 285-288 ◽  
Author(s):  
K. Revathy ◽  
S. R. Prabhakaran Nair ◽  
B. V. Krisha Murthy
Keyword(s):  
Temperature Profile ◽  
Vertical Wind ◽  
Radar Observations ◽  
Mst Radar

scholarly journals Examining Polarimetric Radar Observations of Bulk Microphysical Structures and Their Relation to Vortex Kinematics in Hurricane Arthur (2014)

2017 ◽  
Vol 145 (11) ◽  
pp. 4521-4541 ◽  
Author(s):  
Anthony C. Didlake ◽  
Matthew R. Kumjian
Keyword(s):  
Tropical Cyclone ◽  
Lower Layer ◽  
Polarimetric Radar ◽  
Arthur Prior ◽  
Radar Observations ◽  
Melting Layer ◽  
Ice Particles ◽  
Planar Crystal ◽  
Differential Reflectivity ◽  
Left Quadrant

Dual-polarization radar observations were taken of Hurricane Arthur prior to and during landfall, providing needed insight into the microphysics of tropical cyclone precipitation. A total of 30 h of data were composited and analyzed by annuli capturing storm features (eyewall, inner rainbands, and outer rainbands) and by azimuth relative to the deep-layer environmental wind shear vector. Polarimetric radar variables displayed distinct signatures indicating a transition from convective to stratiform precipitation in the downshear-right to downshear-left quadrants, which is an organization consistent with the expected kinematic asymmetry of a sheared tropical cyclone. In the downshear-right quadrant, vertical profiles of differential reflectivity ZDR and copolar correlation coefficient ρHV were more vertically stretched within and above the melting layer at all annuli, which is attributed to convective processes. An analysis of specific differential phase KDP indicated that nonspherical ice particles had an increased presence in two layers: just above the melting level and near 8-km altitude. Here, convective updrafts generated ice particles in the lower layer, which were likely columnar crystals, and increased the available moisture in the upper layer, leading to increased planar crystal growth. A sharp transition in hydrometeor population occurred downwind in the downshear-left quadrant where ZDR and ρHV profiles were more peaked within the melting layer. Above the melting layer, these signatures indicated reduced ice column counts and shape diversity owing to aggregation in a predominantly stratiform regime. The rainband quadrants exhibited a sharper transition compared to the eyewall quadrants owing to weaker winds and longer distances that decreased azimuthal mixing of ice hydrometeors.

Sign in / Sign up

Export Citation Format

Share Document