Vertically Velocity Characteristics of Oceanic Convection

Jorgensen, David P.; LeMone, Margaret A.

doi:10.1175/1520-0469(1989)046<0621:vvcooc>2.0.co;2

Cited by 214 publications

(143 citation statements)

References 0 publications

Supporting

Mentioning

131

Contrasting

Order By: Relevance

“…The maximum updraft of CMD3 during its lifetime is from 2 m s 1 to 5 m s -1 , approximately identical to that of oceanic convection (Jorgensen and LeMone 1989). This weak updraft allows ample time for warm rain process to produce the precipitation.…”

Section: Characteristics Of Convection Of Medium Depth South Of the Mmentioning

confidence: 87%

Characteristics of Convections of Medium Depth to South of the Meiyu Front Analyzed by Using Numerical Simulation

Zhang

Uyeda

Yamada

et al. 2006

SOLA

View full text Add to dashboard Cite

To further understand the characteristics of the convection of medium depth (CMD) that was introduced by Zhang et al. (2006), the dynamic and thermodynamic aspects of the CMD were examined with the use of a cloud-resolving numerical model. A typical case of the CMD south of the Meiyu front over the east part of continental China, which occurred between 00 UTC and 12 UTC 22 July 2002, was simulated and analyzed.Based on realistic simulation, results of a case study indicated that the CMD possessed the following features: 1) dominated by warm rain process, 2) rapid formation of raindrops and their rapid falling down to the surface, by comparison with those of deep convection. It is expected that the CMD south of the Meiyu front over the east part of continental China shares such characteristics.

show abstract

Section: Characteristics Of Convection Of Medium Depth South Of the Mmentioning

confidence: 87%

Characteristics of Convections of Medium Depth to South of the Meiyu Front Analyzed by Using Numerical Simulation

Zhang

Uyeda

Yamada

et al. 2006

SOLA

View full text Add to dashboard Cite

show abstract

“…Air acceleration into a midlevel mesolow was observed by Sanders and Emanuel (1977) in their case study of an Oklahoma MCS. Taking a horizontal convergence (-D) estimate along the convective line for this case of 1-2* 10-4 s-1 (Jorgensen and LeMone, 1989) as a representative value, the local Coriolis parameter at 23*N (5.8* 10-5 s-1) will make a stretching rate (-fD) of 5.8* 10-8 S-2. With this stretching rate, the mean vorticity in the 850-700 hPa layer of -5.4*10-4 s-1 (Table 1) at the formation stage (1500 UTC 16 June) can be produced in 3 h. The pre-existing vorticity associated with the westward propagating trough could accelerate the process.…”

Section: Discussion and Concluding Remarksmentioning

confidence: 98%

“…Strong cyclonic vorticity and horizontal convergence were associated with this trough as indicated by the P-3 wind measurements. A convergence value of 1-2x103 -s-1 was estimated in the vicinity of this trough using airborne Doppler radar data by Jorgensen and LeMone (1989). The moisture flux convergence over the trough area was also indicated by the distribution of dew point temperatures and winds.…”

Section: Data and Analysesmentioning

confidence: 98%

“…LeMone and Jorgensen (1991) calculated pressure and buoyancy perturbations from the 3-dimensional winds constructed from the airborne Doppler radar data and used the in situ measurements to estimate the momentum flux. Also, Jorgensen and LeMone (1989) studied the vertical velocity characteristics of this case in addition to the other open-ocean MCSs.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Midlevel Vortex Observed in the Taiwan Area Mesoscale Experiment (TAMEX)

Chen

Liang

1992

Journal of the Meteorological Society of Japan

View full text Add to dashboard Cite

A midlevel vortex which occurred during the period of 16-17 June 1987 in the Taiwan Area Mesoscale Experiment (TAMEX) is analyzed in this paper. All of the intensive observational data collected in this period were employed to reveal the structure and evolution of the vortex. These included the conventional surface and upper air observations, conventional and Doppler radar data, and the P-3 aircraft measurements. The cloud top temperatures were also analyzed using enhanced Geostationary Meteorological Satellite (GMS) IR imageries.Analyses showed that this midlevel vortex had a cold, moist core in the middle and lower troposphere (900-550 hPa; 1-5 km) capped by a warm upper troposphere (300-200 hPa) and tilted slightly northwestward towards the mid-tropospheric cold air in the early stage. It developed upward to the 300 hPa (~10 km) warm region and downward to 950 hPa (0.5 km) in the later stage. The horizontal scale of this vortex was about 100-200 km in diameter and the life span was possibly more than 24 h. The heavy rainfall (>125 mm/24 h) over northeastern Taiwan appeared to be due to the combined effects of the enhanced terrain lifting and the particular structure of the maximum wind over northeastern quadrant of this vortex. Based on the overall results, it is proposed that the vertical vortex stretching process coupled with the local topographical effect and the pre-existing vorticity associated with the westward propogating trough was primarily responsible for the formation of this vortex. The reintensification of the vortex during its northward journey over land in the later stage was perhaps mainly due to the intensification of the mesoscale convective systems over the vortex area.

show abstract

“…The traditional physical explanations for these contrasts, also reported in Table 2, are generally based on thermodynamic differences between land and ocean, which in turn are linked to contrasts in the surface properties (Table 3) of crustal materials and liquid water. The stronger heating of the land surface is responsible for greater air-surface temperature contrast and greater instability there (Williams and Renno, 1993), and for the larger updrafts at both cloud base height (Williams and Stanfill, 2002) and at higher levels of deep convection (Jorgenson and LeMone, 1989). The relatively recent upsurge of interest and observational attention to atmospheric aerosol (Molinié and Pontikis, 1995;Rosenfeld and Woodley, 2003;Hicks et al, 2005) has led to alternative physical explanations for the land/ocean contrasts (Table 2) that depend on the regulation of cloud droplet size and compete with the thermodynamic explanations so strongly that the two effects are difficult to distinguish from each other Williams and Stanfill, 2002).…”

Section: The Entangled Roles Of Aerosols and Meteorology In Controllimentioning

confidence: 99%

The scientific basis for a satellite mission to retrieve CCN concentrations and their impacts on convective clouds

et al. 2012

View full text Add to dashboard Cite

Abstract. The cloud-mediated aerosol radiative forcing is widely recognized as the main source of uncertainty in our knowledge of the anthropogenic forcing on climate. The current challenges for improving our understanding are (1) global measurements of cloud condensation nuclei (CCN) in the cloudy boundary layer from space, and (2) disentangling the effects of aerosols from the thermodynamic and meteorological effects on the clouds. Here, we present a new conceptual framework to help us overcome these two challenges, using relatively simple passive satellite measurements in the visible and infared (IR). The idea is to use the clouds themselves as natural CCN chambers by retrieving simultaneously the number of activated aerosols at cloud base, N a , and the cloud base updraft speed. The N a is obtained by analyzing the distribution of cloud drop effective radius in convective elements as a function of distance above cloud base. The cloud base updraft velocities are estimated by double stereoscopic viewing and tracking of the evolution of cloud surface features just above cloud base. In order to resolve the vertical dimension of the clouds, the field of view will be 100 m for the microphysical retrievals, and 50 m for the stereoscopic measurements. The viewing geometry will be eastward and 30 degrees off nadir, with the Sun in the back at 30 degrees off zenith westward, requiring a Sun-synchronous orbit at 14 LST. Measuring simultaneously the thermodynamic environment, the vertical motions of the clouds, their microstructure and the CCN concentration will allow separating the dynamics from the CCN effects. This concept is being applied in the proposed satellite mission named Clouds, Hazards and Aerosols Survey for Earth Researchers (CHASER).

show abstract

Vertically Velocity Characteristics of Oceanic Convection

Cited by 214 publications

References 0 publications

Characteristics of Convections of Medium Depth to South of the Meiyu Front Analyzed by Using Numerical Simulation

Characteristics of Convections of Medium Depth to South of the Meiyu Front Analyzed by Using Numerical Simulation

A Midlevel Vortex Observed in the Taiwan Area Mesoscale Experiment (TAMEX)

The scientific basis for a satellite mission to retrieve CCN concentrations and their impacts on convective clouds

Contact Info

Product

Resources

About