Sensitivity of the Grid-point Atmospheric Model of IAP LASG(GAMILI.I.0)Climate Simulations to Cloud Droplet Effective Radius and Liquid Water Path

This paper documents a study to examine the sensitivity to cloud droplet effective radius and liquid water path and the alleviation the energy imbalance at the top of the atmosphere and at the surface in the latest version of the Grid-point Atmospheric Model of the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics （LASG）, Institute of Atmospheric Physics （IAP） （GAMIL1.1.0）. Considerable negative biases in all flux components, and thus an energy imbalance, are found in GAMIL1.1.0. In order to alleviate the energy imbalance, two modifications, namely an increase in cloud droplet effective radius and a decrease in cloud liquid water path, have been made to the cloud properties used in GAMIL. With the increased cloud droplet effective radius, the single scattering albedo of clouds is reduced, and thus the reflection of solar radiation into space by clouds is reduced and the net solar radiation flux at the top of the atmosphere is increased. With the reduced cloud optical depth, the net surface shortwave radiation flux is increased, causing a net warming over the land surface. This results in an increase in both sensible and latent heat fluxes over the land regions, which is largely balanced by the increased terrestrial radiation fluxes. Consequently, the energy balance at the top of atmosphere and at the surface is achieved with energy flux components consistent with available satellite observations.

Coupling mechanism of THM fields and SLG phases during the gas extraction process and its application in numerical analysis of gas occurrence regularity and effective extraction radius

The analysis of the coupling mechanism of thermal-hydraulic-mechanical(THM)fields,and solid-liquidgas(SLG)phases during gas extraction process is of profound significance to explore its numerical application in the gas occurrence regularity and its effective extraction radius.In this study,the Hudi coal mine in Qinshui basin is taken as the research area,the influencing factors of gas occurrence were analyzed,the differences in overburden load for gas pressure distribution and the factors influencing the effective extraction radius were further discussed by using the COMSOL software.The results show that the derivation of mathematical model in gas extraction shows that the process is a process the THM fields restrict each other,and the SLG phases influence each other.The longer the extraction time,the larger the influencing range of borehole,and the better the extraction effect.The larger the diameter of borehole,the larger the effective extraction radius,and the influence on gas extraction effect is smaller in the early stage and larger in the late stage.The borehole arrangement should be flexibly arranged according to the actual extraction situation.The higher the porosity,the higher the permeability,the better the gas extraction effect.The larger the overburden load of reservoir,the stronger the effective stress,which will result in the more severe the strain,and the closure of pore and fracture,which in turn will lead to the decrease of permeability and slow down the gas extraction.The relationship among extraction time,borehole diameter,negative pressure of gas extraction,permeability with effective extraction radius is exponential.This study has important theoretical and practical significance for clarifying and summarizing the gas occurrence regularity and its engineering practice.

Effect of the Injected Plasma on the Effective Radius of the Magnetic Bubble

Effect of the injected plasma on the effective radius of the magnetic bubble in plasma sail is discussed. Results from solving both the two-dimensional magneto-hydrodynamic（MHD） equations and the magnetic flux conservation equation indicate that the effective radius of the magnetic bubble formed by the pure dipole field is very small, and the rate of the falloff of the magnetic field can be effectively reduced by the inflation of the high-density plasma. The falloff rate of the magnetic field can be r^-1.4. The effective radius of the magnetic bubble can hence be 8.2 km. The effective radius of the magnetic bubble increases about thirty-six times, comparing to the case of the pure dipole field.

Some features of effective radius and variance of dust particles in numerical simulations of the dust climate on Mars

Airborne dust is an important constituent in the Martian atmosphere because of its radiative interaction with the atmospheric circulation.Dust size is one crucial factor in determining this effect.In reality dust sizes are varied;however,in numerical modeling of dust processes,dust size has usually been described by choice of a particular size distribution function,or by use of fixed values of effective radius(ER)and effective variance(EV).In this work,we present analytical expressions that have been derived to specify ER and EV for Nbin dust schemes,based on a model-calculated dust mixing ratio.Numerical simulations based on this approach thus would consider the effects of variable ER on the atmospheric radiation and their interaction.Results have revealed some interesting features of the dust distribution parameters,such as seasonal and spatial variation of ER and EV,which are generally consistent with some previous observational and modeling studies.Compared with the usual approach of using a fixed ER,simulation results from the present approach suggest that the variability of ER can have significant effects on the simulated thermal field of the Martian atmosphere.

Finite Larmor radius magnetohydrodynamic analysis of the ballooning modes in tokamaks

In this paper, the effect of finite Larmor radius （FLR） on high n ballooning modes is studied on the basis of FLR magnetohydrodynamic （FLR-MHD） theory. A linear FLR ballooning mode equation is derived in an ＇s^-- α＇ type equilibrium of circular-flux-surfaces, which is reduced to the ideal ballooning mode equation when the FLR effect is neglected. The present model reproduces some basic features of FLR effects on ballooning mode obtained previously by kinetic ballooning mode theories. That is, the FLR introduces a real frequency into ballooning mode and has a stabilising effect on ballooning modes （e.g., in the case of high magnetic shear s^- ≥ 0.8）. In particular, some new properties of FLR effects on ballooning mode are discovered in the present research. Here it is found that in a high magnetic shear region （s^- ≥ 0.8） the critical pressure gradient （αc,FLR） of ballooning mode is larger than the ideal one （αc,IMHD） and becomes larger and larger with the increase of FLR parameter b0. However, in a low magnetic shear region, the FLR ballooning mode is more unstable than the ideal one, and the αc,FLR is much lower than the αc,IMHD. Moreover, the present results indicate that there exist some new weaker instabilities near the second stability boundary （obtained from ideal MHD theory）, which means that the second stable region becomes narrow.

The Refractive Effect of k-Factor on Radio Propagation over Lokoja, Nigeria

The effective earth radius factor(k-factor)has a refractive propagation effect on transmitted radio signals thus making its study necessary for the proper planning of terrestrial radio links and power budget.This study was carried out over the city of Lokoja,Nigeria,using ten years(2011 to 2020)atmospheric data of temperature,pressure and humidity both at the surface(12 m)and at 100 m AGL.The data were retrieved from European Centre for Medium-Range Weather Forecasts(ECMWF)ERA5.The k-factor yearly variation follows the same trend with minimum and maximum values obtained during dry and wet season months respectively.In addition,the highest mean value of 1.00042 was recorded in the month of August while the lowest value of 1.00040 was recorded in the month of January with an overall mean value of 1.0003.This value is less than the recommended standard of 1.33 by ITU-R.The propagation effect corresponding to k<1.33 is sub-refractive.The implication of this on radio wave propagation,especially terrestrial communications is that transmitted wireless signal is prone to losses.This can be mitigated through an effective power budget:Choice of transmitting antenna’s height and gain,so as to improve the Quality of Service over the study area.

Role of Microphysical Parameterizations with Droplet Relative Dispersion in IAP AGCM 4.1

Previous studies have shown that accurate descriptions of the cloud droplet effective radius （Re） and the autoconversion process of cloud droplets to raindrops （At） can effectively improve simulated clouds and surface precipitation, and reduce the uncertainty of aerosol indirect effects in GCMs. In this paper, we implement cloud microphysical schemes including two-moment Ar and Re considering relative dispersion of the cloud droplet size distribution into version 4.1 of the Institute of Atmospheric Physics＇s atmospheric GCM （IAP AGCM 4.1）, which is the atmospheric component of the Chinese Academy of Sciences＇ Earth System Model. Analysis of the effects of different schemes shows that the newly implemented schemes can improve both the simulated shortwave and longwave cloud radiative forcings, as compared to the standard scheme, in lAP AGCM 4.1. The new schemes also effectively enhance the large-scale precipitation, especially over low latitudes, although the influences of total precipitation are insignificant for different schemes. Further studies show that similar results can be found with the Community Atmosphere Model, version 5.1.

Capillary force of a novel skew-grooved wick structure for micro heat pipes

In order to improve the capillary force of grooved wick, a novel skew-grooved wick structure was proposed for micro heat pipes. Risen meniscus experiments were carried out to research the capillary force of the skew-grooved and rectangle-grooved wick and a comparison of capillarity between the two wick structures was explored. A theoretical capillary force model of skew-grooved wick structure was also developed to calculate its effective capillary radius by comparing with the rectangle-grooved wick. From the experimental results, the maximum capillary force of the skewed-grooved wick is 8.62% larger than that of the rectangle-grooved wick. From the theoretical analysis, because the skewed-grooved wick has a smaller effective capillary radius, its maximum capillary force is 8.64% larger than that of the rectangle-grooved wick. The results indicate that the skew-grooved wick provides larger capillary force than the rectangle-grooved wick.

Comparison of Cloud Properties between Cloud Sat Retrievals and Airplane Measurements in Mixed-Phase Cloud Layers of Weak Convective and Stratus Clouds

Cloud microphysical properties including liquid and ice particle number concentration （NC）, liquid water content （LWC）, ice water content （IWC） and effective radius （RE） were retrieved from CloudSat data for a weakly convective and a widespread stratus cloud. Within the mixed-phase cloud layers, liquid-phase fractions needed to be assumed in the data retrieval process, and one existing linear （Pl） and two exponential （P2 and P3） functions, which estimate the liquid-phase fraction as a function of subfreezing temperature （from -20℃ to 0℃）, were tested. The retrieved NC, LWC, IWC and RE using Pl were on average larger than airplane measurements in the same cloud layer, Function P2 performed better than p1 or P3 in retrieving the NCs of cloud droplets in the convective cloud, while function Pl performed better in the stratus cloud. Function P3 performed better in LWC estimation in both convective and stratus clouds. The REs of cloud droplets calculated using the retrieved cloud droplet NC and LWC were closer to the values of in situ observations than those retrieved directly using the Pl function. The retrieved NCs of ice particles in both convective and stratus clouds, on the assumption of liquid-phase fraction during the retrieval of liquid droplet NCs, were closer to those of airplane observations than on the assumption of function P1.

An Evidence of Aerosol Indirect Effect on Stratus Clouds from the Integrated Ground-Based Measurements at the ARM Shouxian Site

The aerosol effect on clouds was explored using remote sensing of aerosol and cloud data at Shouxian, China. Non-precipitation, ice-free, and overcast clouds were firstly chosen by a combination of sky im- ages from the Total Sky Imager （TSI）, cloud base heights from the Ceilometer, and vertical temperature profiles from the Balloon-Borne Sounding System （BBSS）. Six cases were chosen in summer, and seven in autumn. The averaged cloud effective radii （re）, cloud optical depth （COD）, aerosol total light scattering coefficient （a）, and liquid water path （LWP） are, respectivey, 6.47 μm, 35.4, 595.9 mm-1, 0.19 mm in summer, and 6.07 μm, 96.0, 471.7 mm-1, 0.37 mm in autumn. The correlation coefficient between re and tc was found to change from negative to positive value as LWP increases.

Ground-Based In Situ Measurements of Near-Surface Aerosol Mass Concentration over Anantapur:Heterogeneity in Source Impacts

Surface measurements of aerosol physical properties were made at Anantapur （14.62°N, 77.65°E, 331 m a.s.l）, a semiarid rural site in India, during August 2008-July 2009. Measurements included the segregated sizes of aerosolsas as well as total mass concentration and size distributions of aerosols measured at low relative humidity （RH〈75%） using a Quartz Crystal Microbalance （QCM） in the 25-0.05 um aerodynamic diameter range. The hourly average total surface aerosol mass concentration in a day varied from 15 to 70 ug m-3, with a mean value of 34.02±9.05 ug m-3 for the entire study period. A clear diurnal pattern appeared in coarse, accumulation and nucleation-mode particle concentrations, with two local maxima occurring in early morning and late evening hours. The concentration of coarse-mode particles was high during the summer season, with a maximum concentration of 11.81±0.98 ug m-3 in the month of April, whereas accumulationmode concentration was observed to be high in the winter period contributed 〉68% to the total aerosol mass concentration. Accumulation aerosol mass fraction, Af （= Ma/Mt） was highest during winter （mean value of Af -0.80） and lowest （Af - 0.64） during the monsoon season. The regression analysis shows that both Reff and Rm are dependent on coarse-mode aerosols. The relationship between the simultaneous measurements of daily mean aerosol optical depth at 500 nm （AOD500） and PM2.5 mass concentration （[PM2.5]） shows that surface-level aerosol mass concentration increases with the increase in columnar aerosol optical depth over the observation period.

Characterization of cloud microphysical properties in different cloud types over East Asia based on CloudSat/CALIPSO satellite products

By using four-year CloudSat/CALIPSO satellite data,the authors investigated cloud microphysical properties in three representative regions over East Asia,where models commonly suffer from great biases in simulations of cloud radiative effects.This study aims to provide an observational basis of cloud microphysical properties for the modeling community,against which the model simulations can be validated.The analyzed cloud microphysical properties include mass,number concentration,and effective radius for both liquid and ice phases.For liquid clouds,both cloud mass and number concentration gradually decrease with height,leading to the effective radius being nearly uniformly spread in the range of 8-14μm.For ice clouds,the cloud mass and effective radius decrease with height,whereas the number concentration is nearly uniform in the vertical.The cloud microphysical properties show remarkable differences among different cloud types.Cloud mass and number concentration are larger in cumuliform clouds,whereas smaller in cirrus clouds.By comparing cloud properties among the Tibetan Plateau,East China,and the western North Pacific,results show the values are overall smaller for liquid clouds but larger for ice clouds over the Tibetan Plateau.

IMPACT OF CLOUD DROPLETS SPECTRAL UNCERTAINTY ON MESOSCALE PRECIPITATION

1 INTRODUCTION Cloud radiation is one of the most important and indefinite factors in atmospheric radiation. As shown in a comparative study by Cess et al. with a climate model, differences can be very large in the outcome of varying schemes of cloud parameterization. It is therefore of great significance to have a relatively accurate scheme of cloud parameterization for the atmospheric radiative transfer process. According to the Mie＇s scattering theory, the scale parameter of the particulate has a very important effect on its optical property. It is then seen that the number concentration and size distribution of cloud droplets play an important in the determination of the optical properties of cloud droplets.

Tabooed Universal Characteristic Length and Misled Boiling Heat Transfer Research

The paper presents the next step within multiyear fruitless efforts of the author to overcome the absurd situation in boiling heat transfer research. The focus is made on the problem of the characteristic length of the process most clearly exhibiting the consequences of half a century ignoring the basic MTD （Model ＂theater of director＂）, the UC （Universal correlation） and some other boiling fundamentals. Echoing control of boiling heat transfer by nucleation, the MTD-UC identifies universal characteristic length, the AER （Average effective radius） of nucleation sites, equally workable at the macro- and microscale. Inefficiency of the generally accepted, so called MTA （theater of actors） is particularly pronounced just in the confusion with the characteristic length. Traditional and potential candidates, departure diameter of vapor bubble and transverse internal size of the channel hardly can be adjusted to independence of developed boiling HTC on mass acceleration, subcooling, liquid convection and the heating surface geometry. At the same time, even such a problem has not prevented many authors to develop tens or even hundreds of helpless MTA-based correlations. The ignoring the MTD-UC-AER has also led to the incompleteness of the standard boiling heat transfer experiment, which is usually done without studying nucleation sites （there are available only very few comprehensive experimental works including the data on the AER）. The only exception was made for the problem of boiling heat transfer enhancement： over the past decades enhanced boiling surfaces were developed in direct accordance with the principle defined by the MTD-UC （just through the AER）. Another thing is that the basic role of the MTD-UC-AER in substantial progress of the relevant R＆D activities passed over in silence in the corresponding publications. Enviable unity and coherence of heat transfer community in preventing real scientific debate on the problem is also remarked.

Polaron effects in cylindrical GaAs/Al_xGa_(1-x)As core-shell nanowires

By the fractal dimension method, the polaron properties in cylindrical GaAs/AlxGa1-xAs core-shell nanowire are explored. In this study, the polaron effects in GaAs/AlxGa1-xAs core-shell nanowire at different values of shell width and aluminum concentration are discussed. The polaron binding energy, polaron mass shift and fractal dimension parameter are numerically worked out each as a function of core radius. The calculation results show that the binding energy and mass shift of the polaron first increase and then decrease as the core radius increases, forming their corresponding maximum values for different aluminum concentrations at a given shell width. Polaron problems in the cylindrical GaAs/AlxGa1-xAs core-shell nanowire are solved simply by using the fractal dimension method to avoid complex and lengthy calculations.

Electron Transport under the Influence of Two Kinds of Friction in an Electron-Deuteron Plasma

We discuss an electron transport in an ideal plasma which consists of electrons and deuterons. With respect to a frictional force to suppress an unlimited increase of a drift velocity, the Boltzmann equation with the Fokker-Planck collision term takes into consideration only a dynamical frictional force coming from the many-body collisions through the Coulomb force. However, we here bring forward a problem that there may be another frictional force besides the dynamical frictional force. Another frictional force was found in the weakly ionized plasma and appears only in the case where free paths (nearly straight lines in no external force field) can be defined. Then, we have inquired into the existence of physical quantities like free paths (or free times) in the field of the scattering through the Coulomb force and the existence of an effective radius of the Coulomb force of a deuteron.

The effective hydrodynamic radius in the Stokes-Einstein relation is not a constant

Variants based on the assumption of effective hydrodynamic radius being a constant are usually adopted to test the Stokes-Einstein(SE)relation.The rationality of the assumption is examined by performing molecular dynamics simulations with the truncated Lennard-Jones-like(TLJ)model,Kob-Andersen model and ortho-terphenyl(OTP)model.The results indicate the assumption is generally not established except for special case.The effective hydrodynamic radius is observed to increase with decreasing temperature for TLJ model but is decreased for Kob-Andersen and OTP model;and which is almost a constant for TLJ particle with enough rigidity.The variant of SE relation D~Th is invalid for the three models except for the TLJ particle with enough rigidity.We propose similar inconsistency may be also existed in other liquids and the assumption should be critically evaluated when adopted to test the SE relation.

Effects of geotextile envelope and perforations on the performance of corrugated drain pipes

Subsurface drainage is an important agriculture drainage measure.It is primary to select suitable drain pipes and envelopes for efficient subsurface drainage.And now,corrugated drains and geotextile envelopes are widely used.However,the effects of geotextile envelopes and perforations on the drainage of corrugated drains are not well understood.This study conducted a series of sand tank experiments of steady-state flow with or without geotextile envelopes and with different perforation patterns.The drainage flow and the profile head distributions were analyzed and compared.Furthermore,the applicability of theoretical formulas,which are used to calculate effective radius considering the resistance of different perforation patterns,was evaluated.Results showed that the geotextile envelope weakened the effect of perforations on streamlines,thereby causing the value of effective radiuses to be close to that of the actual radius.The drainage flow of the drain with a geotextile envelope was six times that of the bare drain.The relationship between drainage flow and opening area could be described by inverse proportional function.Meanwhile,the drainage flow was affected by the perforation arrangement.Drain with small longitudinal perforation spacing had a drainage flow of approximately 15%larger than that with wider longitudinal perforation spacing.The bottom perforations drained out first and most,and the drainage flow of the drain opened at the bottom could be 11%higher than that at the top.Low-efficiency perforations cause higher head loss near the pipe wall.Existing formulas of entrance resistance were not suitable for geotextile-wrapped corrugated drains,the effect of geotextile envelope and orifice entrance loss at perforations should be considered.

Studies on seepage law considering stratigraphic dips

Currently,water injection is widely used for oil field developments.For reservoirs with complex geological structures,large stratigraphic dip angles,low porosities and extra-low permeabilities,the effect of water injection is not satisfying.This paper establishes a modified radial flow formula on the dip angle,and uses the plane radial seepage theory to get formation pressure distributions and a production formula in tilted strata.For injectors with their threshold pressures greater than their formation in-situ pressures,the effective radius for waterflooding is derived for a given injection pressure and then it is used to evaluate waterflooding effect and well pattern suitability,and guide the oilfield production.This method can also be applied to other waterflooding oilfields with similar geological conditions.

Gyrokinetic Simulation of Magnetic Compressional Modes in General Geometry

A method for gyrokinetic simulation of low frequency(lower than the cyclotron frequency)magnetic compressional modes in general geometry is presented.The gyrokinetic-Maxwell system of equations is expressed fully in terms of the compressional component of the magnetic perturbation,δBk,with finite Larmor radius effects.This introduces a"gyro-surface"averaging ofδBk in the gyrocenter equations of motion,and similarly in the perpendicular Ampere’s law,which takes the form of the perpendicular force balance equation.The resulting system can be numerically implemented by representing the gyro-surface averaging by a discrete sum in the configuration space.For the typical wavelength of interest(on the order of the gyroradius),the gyro-surface averaging can be reduced to averaging along an effective gyro-orbit.The phase space integration in the force balance equation can be approximated by summing over carefully chosen samples in the magnetic moment coordinate,allowing for an efficient numerical implementation.