scholarly journals Integrated water vapor during active and break spells of monsoon and its relationship with temperature, precipitation and precipitation efficiency over a tropical site

2021 ◽  
Author(s):  
Nirmala Bai Jadala ◽  
Miriyala Sridhar ◽  
Gopa Dutta ◽  
Mohammed Yousuf ◽  
Y.K. Reddy
Keyword(s):  
Water Vapor ◽  
Precipitation Efficiency

scholarly journals Intensification of Precipitation Extremes with Warming in a Cloud-Resolving Model

2011 ◽  
Vol 24 (11) ◽  
pp. 2784-2800 ◽  
Author(s):  
Caroline J. Muller ◽  
Paul A. O’Gorman ◽  
Larissa E. Back
Keyword(s):  
Water Vapor ◽  
Climate Model ◽  
Atmospheric Temperature ◽  
Precipitation Extremes ◽  
Temperature Structure ◽  
Precipitation Efficiency ◽  
Fractional Rate ◽  
Cloud Resolving Model ◽  
Climate Model Simulations ◽  
Static Energy

Abstract A cloud-resolving model is used to investigate the effect of warming on high percentiles of precipitation (precipitation extremes) in the idealized setting of radiative-convective equilibrium. While this idealized setting does not allow for several factors that influence precipitation in the tropics, it does allow for an evaluation of the response of precipitation extremes to warming in simulations with resolved rather than parameterized convection. The methodology developed should also be applicable to less idealized simulations. Modeled precipitation extremes are found to increase in magnitude in response to an increase in sea surface temperature. A dry static energy budget is used to relate the changes in precipitation extremes to changes in atmospheric temperature, vertical velocity, and precipitation efficiency. To first order, the changes in precipitation extremes are captured by changes in the mean temperature structure of the atmosphere. Changes in vertical velocities play a secondary role and tend to weaken the strength of precipitation extremes, despite an intensification of updraft velocities in the upper troposphere. The influence of changes in condensate transports on precipitation extremes is quantified in terms of a precipitation efficiency; it does not change greatly with warming. Tropical precipitation extremes have previously been found to increase at a greater fractional rate than the amount of atmospheric water vapor in observations of present-day variability and in some climate model simulations with parameterized convection. But the fractional increases in precipitation extremes in the cloud-resolving simulations are comparable in magnitude to those in surface water vapor concentrations (owing to a partial cancellation between dynamical and thermodynamical changes), and are substantially less than the fractional increases in column water vapor.

scholarly journals Precipitation Efficiency and Water Budget of Typhoon Fitow (2013): A Particle Trajectory Study

2017 ◽  
Vol 18 (9) ◽  
pp. 2331-2354 ◽  
Author(s):  
Huiyan Xu ◽  
Guoqing Zhai ◽  
Xiaofan Li
Keyword(s):  
Water Vapor ◽  
Dispersion Model ◽  
Wrf Model ◽  
Particle Dispersion ◽  
Precipitation Efficiency ◽  
Accumulated Rainfall ◽  
Torrential Rainfall ◽  
High Precipitation ◽  
Particles Trajectories ◽  
Water Vapor Convergence

Abstract In this study, the WRF Model is used to simulate the torrential rainfall of Typhoon Fitow (2013) over coastal areas of east China during its landfall. Data from the innermost model domain are used to trace trajectories of particles in three major 24-h accumulated rainfall centers using the Lagrangian flexible particle dispersion model (FLEXPART). Surface rainfall budgets and cloud microphysical budgets as well as precipitation efficiency are analyzed along the particles’ trajectories. The rainfall centers with high precipitation efficiency are associated with water vapor convergence, condensation, accretion of cloud water by raindrops, and raindrop loss/convergence. The raindrop loss/convergence over rainfall centers is supported by the raindrop gain/divergence over the areas adjacent to rainfall centers. Precipitation efficiency is mainly determined by hydrometeor loss/convergence. Hydrometeor loss/convergence corresponds to the hydrometeor flux convergence, which may be related to the increased vertical advection of hydrometeors in response to the upward motions and upward decrease of hydrometeors, whereas hydrometeor gain/divergence corresponds to the reduction in hydrometeor flux convergence, which may be associated with the decreased horizontal advection of hydrometeors in response to the zonal decrease in hydrometeors and easterly winds and the meridional increase in hydrometeors and southerly winds. The water vapor convergence and associated condensation do not show consistent relationships with orographic lifting all the time.

scholarly journals Pairing Measurements of the Water Vapor Isotope Ratio with Humidity to Deduce Atmospheric Moistening and Dehydration in the Tropical Midtroposphere

2012 ◽  
Vol 25 (13) ◽  
pp. 4476-4494 ◽  
Author(s):  
David Noone
Keyword(s):  
Water Vapor ◽  
Isotope Ratio ◽  
Large Scale ◽  
Isotopic Ratio ◽  
Atmospheric Humidity ◽  
Precipitation Efficiency ◽  
Using Data ◽  
Water Vapor Mixing Ratio ◽  
The Tropics ◽  
The Western Pacific

Abstract Measurements of the isotope ratio of water vapor (expressed as the δ value) allow processes that control the humidity in the tropics to be identified. Isotopic information is useful because the change in δ relative to the water vapor mixing ratio (q) is different for different processes. The theoretical framework for interpreting paired q–δ data is established and based on a set of simple models that account for mixing and a range of condensation conditions. A general condensation model is derived that accounts for cloud precipitation efficiency and postcondensation exchange. Using data from the Tropospheric Emission Spectrometer (TES), aspects of subtropical hydrology are characterized by the match between theoretical curves and observed displacement in q–δ space. The subtropics are best described as the balance between drying associated with (mostly horizontal) transport of dry air from high latitudes and moistening by clouds with low precipitation efficiency. In the western Pacific moistening involves the import of air into which raindrops have evaporated and is identified by “super-Rayleigh” isotopic distillation. In the dry subtropics, the observations are consistent with the condensation–advection explanation for the humidity minimum but also reflect details of the cloud processes and moistening by high humidity filaments of tropical origin. In spite of limitations of the TES data, the success of the analysis highlights the value of using isotopic data in analysis of tropospheric moisture budgets and the role water isotopic ratio measurements can play in identifying mechanisms associated with large-scale changes in atmospheric humidity.

scholarly journals Impact of increased water vapor on precipitation efficiency over northern Eurasia

2014 ◽  
Vol 41 (8) ◽  
pp. 2941-2947 ◽  
Author(s):  
Hengchun Ye ◽  
Eric J. Fetzer ◽  
Sun Wong ◽  
Ali Behrangi ◽  
Edward T. Olsen ◽  
...  
Keyword(s):  
Water Vapor ◽  
Northern Eurasia ◽  
Precipitation Efficiency

scholarly journals Soil moisture control of precipitation re-evaporation over a heterogeneous land surface

2021 ◽  
Author(s):  
Yu Cheng ◽  
Pak Wah Chan ◽  
Xin Wei ◽  
Zeyuan Hu ◽  
Zhiming Kuang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Vapor ◽  
Land Surface ◽  
Surface Precipitation ◽  
Precipitation Efficiency ◽  
Homogeneous Soil ◽  
Atmospheric Profile ◽  
Soil Moisture Heterogeneity ◽  
The Given ◽  
Water Vapor Convergence

AbstractSoil moisture heterogeneity can induce mesoscale circulations due to differential heating between dry and wet surfaces, which can, in turn, trigger precipitation. In this work, we conduct cloud-permitting simulations over a 100 km × 25 km idealized land surface, with the domain split equally between a wet and dry region, each with homogeneous soil moisture. In contrast to previous studies that prescribed initial atmospheric profiles, each simulation is run with fixed soil moisture for 100 days to allow the atmosphere to equilibrate to the given land surface rather than prescribing the initial atmospheric profile. It is then run for one additional day, allowing the soil moisture to freely vary. Soil moisture controls the resulting precipitation over the dry region through three different mechanisms: as the dry domain gets drier, (1) the mesoscale circulation strengthens, increasing water vapor convergence over the dry domain, (2) surface evaporation declines over the dry domain, decreasing water vapor convergence over the dry domain and (3) precipitation efficiency declines due to increased re-evaporation, meaning proportionally less water vapor over the dry domain becomes surface precipitation. We find that the third mechanism dominates when soil moisture is small in the dry domain: drier soils ultimately lead to less precipitation in the dry domain due to its impact on precipitation efficiency. This work highlights an important new mechanism by which soil moisture controls precipitation, through its impact on precipitation re-evaporation and efficiency.

Dimension Characteristics and Precipitation Efficiency of Cumulonimbus Clouds in the Region Far South from the Mei-Yu Front over the Eastern Asian Continent

2006 ◽  
Vol 134 (7) ◽  
pp. 1942-1953 ◽  
Author(s):  
Yukari Shusse ◽  
Kazuhisa Tsuboki
Keyword(s):  
Water Vapor ◽  
Water Cycle ◽  
Rainfall Amount ◽  
Cloud Base ◽  
Strong Positive Correlation ◽  
Total Rainfall ◽  
Asian Continent ◽  
Maximum Rainfall ◽  
Precipitation Efficiency ◽  
Cumulonimbus Clouds

Abstract Dimension characteristics in precipitation properties of cumulonimbus clouds are basic parameters in understanding the vertical transport of water vapor in the atmosphere. In this study, the dimension characteristics and precipitation efficiency of cumulonimbus clouds observed in the Global Energy and Water Cycle Experiment (GEWEX) Asian Monsoon Experiment (GAME) Huaihe River Basin Experiment (HUBEX) are studied using data from X-band Doppler radars and upper-air soundings. The maximum echo area (EAmax) of the cumulonimbus clouds ranged from 0.5 to 470 km2, and the maximum echo top (ETmax) ranged from 2 to 19 km. The total number of cells (TNC) within the cumulonimbus clouds over their lifetime was from 1 to 25. The ETmax, TNC, area time integral (ATI), and total rainfall amount (Rtot) strongly correlate with the EAmax of the cumulonimbus clouds. The cell-averaged ATI (ATIcell = ATI/TNC), maximum rainfall intensity (RImax), and cell-averaged rainfall amount (Rcell = Rtot/TNC) increase when the EAmax is smaller than 100 km2. On the other hand, they are almost constant when the EAmax is larger than 100 km2. The rain productivity of small clouds (<100 km2 in EAmax) increases not only by the increase of the TNC but also by the intensification of cells, while that of large cumulonimbus clouds (>100 km2 in EAmax) increases by the increase of the TNC rather than by the intensification of cells. In the present study, precipitation efficiency (ɛp) is defined as the ratio of the total rainfall amount (Rtot) to the total water vapor amount ingested into the cloud through the cloud base (Vtot). The ɛp was calculated for six clouds whose vertical velocity data at the cloud-base level were deduced by dual-Doppler analysis throughout their lifetime. The ɛp ranged from 0.03% to 9.31% and exhibited a strong positive correlation with the EAmax. This indicates that more than 90% of the water vapor that enters the clouds through the cloud base is consumed to moisten the atmosphere and less than 10% is converted to precipitation and returned to the ground. The cumulonimbus clouds in the region far south from the mei-yu front over the eastern Asian continent efficiently transport water vertically and humidify the upper troposphere.

New Design for a Differentially Pumped Hydration Chamber for a Siemens IA

1971 ◽  
Vol 29 ◽  
pp. 44-45
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Electron Microscopy ◽  
Water Vapor ◽  
Electron Diffraction ◽  
Water Vapor Pressure ◽  
Biological Materials ◽  
Thin Membrane ◽  
Reliable System ◽  
System A ◽  
Water Films ◽  
Aperture Opening

Electron microscopy and diffraction of biological materials in the hydrated state requires the construction of a chamber in which the water vapor pressure can be maintained at saturation for a given specimen temperature, while minimally affecting the normal vacuum of the remainder of the microscope column. Initial studies with chambers closed by thin membrane windows showed that at the film thicknesses required for electron diffraction at 100 KV the window failure rate was too high to give a reliable system. A single stage, differentially pumped specimen hydration chamber was constructed, consisting of two apertures (70-100μ), which eliminated the necessity of thin membrane windows. This system was used to obtain electron diffraction and electron microscopy of water droplets and thin water films. However, a period of dehydration occurred during initial pumping of the microscope column. Although rehydration occurred within five minutes, biological materials were irreversibly damaged. Another limitation of this system was that the specimen grid was clamped between the apertures, thus limiting the yield of view to the aperture opening.

Hydration Chamber for Jeolco 200 Kv Microscope

1970 ◽  
Vol 28 ◽  
pp. 542-543
Author(s):  
V. R. Matricardi ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Electron Microscope ◽  
Water Vapor ◽  
Vapor Pressure ◽  
Pressure Gradient ◽  
Room Temperature ◽  
List Type ◽  
Type Number ◽  
Equilibrium Vapor Pressure

In order to observe room temperature hydrated specimens in an electron microscope, the following conditions should be satisfied: The specimen should be surrounded by water vapor as close as possible to the equilibrium vapor pressure corresponding to the temperature of the specimen.The specimen grid should be inserted, focused and photo graphed in the shortest possible time in order to minimize dehydration.The full area of the specimen grid should be visible in order to minimize the number of changes of specimen required.There should be no pressure gradient across the grid so that specimens can be straddled across holes.Leakage of water vapor to the column should be minimized.

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