scholarly journals Preliminary results on the simulation of the 1999 Orissa super cyclone using a GCM with a new boundary layer code

MAUSAM ◽  
2021 ◽  
Vol 57 (1) ◽  
pp. 119-128
Author(s):  
T. N. VENKATESH ◽  
VIDYADHAR MUDKAVI ◽  
S. RAJALAKSHMY ◽  
V. R. SARASAMMA ◽  
U. N. SINHA ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Initial Conditions ◽  
Surface Force ◽  
Maximum Error ◽  
Horizontal Resolution ◽  
Surface Forces ◽  
Preliminary Results ◽  
Eddy Fluxes ◽  
Super Cyclone

& bl 'kks/k&Ik= esa ,u- ,e- vkbZ- Vh- ,y- vkbZ- ifj;kstuk ds ,d Hkkx ds :Ik esa fy[ks x, ,d u, ,- th- lh- ,e- dksM+ ¼uker% o"kkZ½ dk mi;ksx djrs gq, mM+hlk ds egkpØokr ds izfr:i.k  ls izkIr fd, x, izkjfEHkd ifj.kkeksa dks izLrqr fd;k x;k gSA bZ- lh- ,e- MCY;w- ,Q-  Vh-&106 dh vkjfEHkd voLFkkvksa dk mi;ksx djrs gq, 26 vDrwcj] 1999 dks 0000 ;w- Vh- lh- ij bl izfr:i.k dks vkjEHk fd;k x;k gSA gok ds >ksadsiu ds dkjd dks lfEefyr djrs gq, ekud eksuhu&vkscw[kkso ifjlhek Lrj dksM ls Vh&80 ds foHksnu ij o"kkZ dksM dk mi;ksx djrs gq, daVªksy ju fd;k x;k gSA 78 fd-eh- xzhM varjky ls 120 LisDVªy ekWMl esa mUur {kSfrt foHksnu vkSj eUn iouksa ij u, ifjlhek Lrj ds izkpyhdj.k ls dksM vla[; o`f);ksa dks n’kkZrk gS% izfr:i.k dks vkjEHk djus ds i'pkr~ vf/kdre =qfV esa 36 ?kaVksa dh vof/k esa 350 ls 234 fd-eh-] 48 ?kaVksa dh vof/k esa 310 ls 34 fd-eh- vkSj 96 ?kaVksa dh vof/k esa 410 ls 55 fd-eh- rd =qfV;ksa dh vf/kdre deh ikbZ xbZ gSA blesa ;g lq>ko fn;k x;k gS fd bl o`f) dk Js; i`"Bh; cyksa ds mUur vkdyu vkSj u, ifjlhek Lrj cy vk?kw.kZ ¼VkdZ½ dksM esa fufgr gSA blesa cy vk?kw.kZ ¼VkdZ½ dh Hkwfedk izeq[k ;ksxnku ds :Ik esa gh gS tksfd fo’ks"k :i ls pØokrksa dh i`"B Hkwfe ls lacaf/kr gSa tgk¡ ij iousa rqyukRed :i ls gYdh gksrh gSa fdarq ml {ks= esa fo|eku i`"Bh; cy rFkk bldh vk?kw.kZ Hkqtk ¼ewesaV vkeZ½ nksuksa vf/kd gksrh gSaA vk’p;Ztud :Ik ls mPprj i`"Bh; cy u, dksM }kjk iwokZuqekfur mPprj iouksa ls Hkh mRiUu gksrs gSaA blesa jkspd ckr ;g gS fd bldh i`"B Hkwfe pØokr ds ekxZ vkSj U;wure vonkc nksuksa esa u, ifjlhek Lrj ekM;wy ls mPprj foHksnu ds dkj.k gqbZ o`f)  ls cgqr vf/kd lacaf/kr gSA pØokr iFk iwokZuqeku ij vU; Hkaoj ¶yDlksa ¼laos| m"ek] vknzZrk½ ds izHkko dk ewY;k¡du djus ds fy, vkSj vf/kd fo’ys"k.k djuk vko’;d gSA We present here preliminary results from the simulation of the Orissa super cyclone using a new AGCM code (named Varsha) written as part of a NMITLI project. The simulation is initialized at 0000 UTC, 26 October 1999, using ECMWF T-106 initial conditions. The control run is made using the Varsha code at a T-80 resolution with a standard Monin-Obukhov boundary layer code incorporating a gustiness factor. With the horizontal resolution improved to 120 spectral modes with a 78 km grid spacing, and a new boundary layer parameterization at low winds, the code shows substantial improvements: the maximum error is reduced from 350 to 234 km at 36 hr after initialization, 310 to 34 km at 48 hr, and 410 to 55 km at 96 hr. It is suggested that part of the explanation for this improvement lies in the improved estimation of surface forces and torque in the new boundary layer code. The role of torque is particularly interesting as the major contribution to it comes from the outer regions of the cyclone where the winds are relatively low but the area on which the surface force acts and its moment arm are both high. Intriguingly the higher surface forces arise also from the higher winds predicted by the new code. An interesting finding is that, on both track and minimum pressure, the improvement due to higher resolution is greater with the new boundary layer module. Further analysis is necessary to assess the effect of other eddy fluxes (sensible heat, moisture) on cyclone track prediction.

Surface Forces and Adhesion Between Dissimilar Materials Measured in Various Environments

1989 ◽  
Vol 170 ◽  
Author(s):  
Douglas T. Smith ◽  
Roger G. Horn
Keyword(s):  
Aqueous Solution ◽  
Silica Surface ◽  
Dissimilar Materials ◽  
Surface Force ◽  
Surface Forces ◽  
Mica Surface ◽  
Surface Force Apparatus ◽  
Preliminary Results ◽  
Silica Surfaces ◽  
The Past

AbstractThe Israelachvili surface force apparatus has been used extensively over the past decade to make detailed measurements of surface forces and adhesion between very smooth solids in various liquid and vapor environments. Most of those measurements have been made with mica surfaces, but we have recently developed a method of preparing smooth silica surfaces for use in place of the mica. The silica surfaces adhere in dry and humid atmospheres, but do not adhere when immersed in water.The use of a second material not only broadens the scope of the Israelachvili technique, but also enables studies of forces and adhesion between dissimilar materials. In this work, we present the results of measurements of adhesion in air and forces in aqueous solution between two silica surfaces; we also report preliminary results of the adhesion between a mica surface and a silica surface.

scholarly journals Examination of WRF-ARW Experiments Using Different Planetary Boundary Layer Parameterizations to Study the Rapid Intensification and Trajectory of Hurricane Otto (2016)

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1317
Author(s):  
Tito Maldonado ◽  
Jorge A. Amador ◽  
Erick R. Rivera ◽  
Hugo G. Hidalgo ◽  
Eric J. Alfaro
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Initial Conditions ◽  
Surface Wind ◽  
Regional Model ◽  
Horizontal Resolution ◽  
Economic Losses ◽  
Rapid Intensification ◽  
Medium Range Forecast ◽  
Meteorological Features

Hurricane Otto (2016) was characterised by remarkable meteorological features of relevance for the scientific community and society. Scientifically, among the most important attributes of Otto is that it underwent a rapid intensification (RI) process. For society, this cyclone severely impacted Costa Rica and Nicaragua, leaving enormous economic losses and many fatalities. In this study, a set of three numerical simulations are performed to examine the skill of model estimations in reproducing RI and trajectory of Hurricane Otto by comparing the results of a global model to a regional model using three different planetary boundary layer parameterizations (PBL). The objective is to set the basis for future studies that analyse the physical reasons why a particular simulation (associated with a certain model setup) performs better than others in terms of reproducing RI and trajectory. We use the regional model Weather Research and Forecasting—Advanced Research WRF (WRF-ARW) with boundary and initial conditions provided by the Global Forecast System (GFS) analysis (horizontal resolution of 0.5 degrees). The PBL used are the Medium Range Forecast, the Mellor-Yamada-Janjic (MYJ), and the Yonsei University (YSU) parameterizations. The regional model is run in three static domains with horizontal grid spacing of 27, 9 and 3 km, the latter covering the spacial extent of Otto during the simulation period. WRF-ARW results improve the GFS forecast, in almost every aspect evaluated in this study, particularly, the simulated trajectories in WRF-ARW show a better representation of the cyclone path and movement compared to GFS. Even though the MYJ experiment was the only one that exhibited an abrupt 24-h change in the storm’s surface wind, close to the 25-knot threshold, the YSU scheme presented the fastest intensification, closest to reality.

scholarly journals Numerical prediction of the Orissa super cyclone (1999) : Sensitivity to the parameterisation of convection, boundary layer and explicit moisture processes

MAUSAM ◽  
2021 ◽  
Vol 57 (1) ◽  
pp. 61-78
Author(s):  
DODLA VENKATA BHASKAR RAO ◽  
DASARI HARI PRASAD
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Numerical Prediction ◽  
Convection Boundary Layer ◽  
Cyclone Track ◽  
Warm Core ◽  
Boundary Layer Processes ◽  
Super Cyclone ◽  
Fine Resolution

& ih- ,l- ;w- @ ,u- lh- ,- vkj-   ,e- ,e- 5 dk mi;ksx djds mM+hlk esa 1999 esa vk, egkpØokr dh xfrfof/k;ksa vkSj mldh rhozrk ds la[;kRed iwokZuqeku dk bl 'kks/k&i= esa v/;;u fd;k x;k gSA laogu] xzgh; ifjlhek Lrj vkSj fuf’pr ueh Ldheksa dh izkpyhdj.k  ;kstukvksa dh Hkwfedk dk v/;;u djus ds fy, laosnu’khyrk iz;ksx fd, x, gSaA caxky dh [kkM+h esa 90] 30 vkSj 10 fd-eh- {kSfrt varjkyksa ds rhu ikjLifjd iz{ks=ksa ¼Mksesu½ dk irk yxkus ds fy, bl ekWMy dh ifjdYiuk dh xbZ gSA ,d va’k ds varjky ij miyC/k gq, ,u- lh- bZ- ih-  ,Q- ,u- ,y-  vk¡dM+ksa dk mi;ksx djds izkjafHkd {ks=ksa vkSj fHkUu le; ds ifjlhek ifjorhZ rFkk 12 ?kaVs ds varjky ij leqnz lrg rkieku miyC/k djk, x, gSaA laogu] xzgh; ifjlhek Lrj vkSj fuf’pr ueh izfØ;kvksa ds laca/k esa pØokr ds ekxZ dk iwokZuqeku vkSj mldh rhozrk dh laosnu’khyrk dk v/;;u djus ds fy, rhu iz;ksx fd, x, gSaA blls izkIr gq, ifj.kkeksa ls pØokr ds ekxZ ds iwokZuqeku esa laoguh; izfØ;kvksa dh egRoiw.kZ Hkwfedk dk irk pyk gS rFkk dSu&fÝ’k 2 Ldhe ls pØokr ds ekxZ dk lcls lVhd <ax ls irk yxk;k tk ldk gSA blds vykok ;g irk pyrk gS fd xzgh; ifjlhek Lrj izfØ;k,¡ esyj&;eknk Ldhe ds lg;ksx ls lcls izpaMre pØokr dh rhozrk dks Kkr dj ldrh gSaA fuf’pr ueh izfØ;k,¡ pØokr  dh xfr dks fu;af=r djrh gSa tks Hkhrjh iz{ks= ¼Mksesu½  ds 10 fd-eh- ds lw{e foHksnu ds QyLo:Ik laHko gks ldrk gSA dSu&fÝz’k 2 vkSj esyj&;eknk dh la;qDr pj.kc) ;kstuk ls pØokr ds ekxZ vkSj mldh rhozrk ds laca/kksa dks csgrj <ax ls izfr:fir fd;k x;k gSA fdlh ,dek= iz;ksx dh rqyuk esa lHkh feystqys iz;ksxksa ls pØokr ds ekxZ vkSj mldh rhozrk dk csgrj vkdyu fd;k tk ldk gSA izfr:fir pØokr esa ,diw.kZ fodflr pØokr ds] m".k ØksM] dsanz vkSj dsanz&fHkfRr tSls lHkh y{k.k ik, x, gSaA ekWMy ls izfr:fir o"kkZ forj.k vkSj rhozrk izs{k.kksa ds vuq:Ik ikbZ xbZ gSA Numerical prediction of the movement and intensification of the Orissa Super Cyclone (1999) is studied using PSU/NCAR MM5. Sensitivity experiments were made to study the role of the parameterisation schemes of convection, planetary boundary layer and explicit moisture schemes. The model is designed to have three interactive domains with 90, 30 and 10 km horizontal resolutions covering the Bay of Bengal region. The initial fields and time varying boundary variables and sea surface temperatures at 12 hour interval are provided from NCEP FNL data available at 1° resolution. Three groups of experiments were performed to study the sensitivity of the cyclone track prediction and intensification to the schemes of convection, planetary boundary layer and explicit moisture processes. The results indicate that convective processes play an important role in the cyclone track prediction and the scheme of Kain-Fritsch 2 produces the best track and the planetary boundary layer processes control the intensification with the scheme of Mellor-Yamada producing the strongest cyclone. The explicit moisture processes modulate the movement of the cyclone, which may be due to the fine resolution of the 10 km for the innermost domain. The mixed-phase scheme in combination with Kain-Fritsch 2 and Mellor-Yamada produce the best simulation in terms of the track as well as intensification. The ensemble mean of all the conducted experiments estimate the track positions and intensification better than any individual experiment. The simulated cyclone shows all the characteristics of a mature cyclone, with warm core, formation of the eye and eye wall. The model simulated rainfall distribution and intensity have good agreement with the observations.

On the Behavior of the Stable Boundary Layer and the Role of Initial Conditions

2006 ◽  
pp. 1811-1829
Author(s):  
Xingzhong Shi ◽  
Richard T. McNider ◽  
M. P. Singh ◽  
David E. England ◽  
Mark J. Friedman ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Stable Boundary Layer ◽  
Initial Conditions ◽  
Stable Boundary

On the Behavior of the Stable Boundary Layer and the Role of Initial Conditions

2005 ◽  
Vol 162 (10) ◽  
pp. 1811-1829 ◽  
Author(s):  
Xingzhong Shi ◽  
Richard T. McNider ◽  
M. P. Singh ◽  
David E. England ◽  
Mark J. Friedman ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Stable Boundary Layer ◽  
Initial Conditions ◽  
Stable Boundary

The role of substrate interactions in the modification of surface forces by self-assembled monolayers

RSC Advances ◽  
2014 ◽  
Vol 4 (32) ◽  
pp. 16803-16812 ◽  
Author(s):  
B. W. Ewers ◽  
J. D. Batteas
Keyword(s):  
Surface Force ◽  
Surface Forces ◽  
Self Assembled Monolayers ◽  
Strain Mapping ◽  
Substrate Interactions ◽  
Assembled Monolayers ◽  
Self Assembled

Detailed pressure and strain mapping of atomistic contact simulations elucidate the mechanical and tribochemical mechanisms of surface force modification with SAMs.

scholarly journals Effects of Initial and Boundary Conditions of Mesoscale Models on Simulated Atmospheric Refractivity

2012 ◽  
Vol 51 (1) ◽  
pp. 115-132 ◽  
Author(s):  
Changgui Wang ◽  
Damian Wilson ◽  
Tracy Haack ◽  
Peter Clark ◽  
Humphrey Lean ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Initial Conditions ◽  
Weather Prediction ◽  
Horizontal Resolution ◽  
Atmospheric Environment ◽  
Initial State ◽  
Weather Patterns ◽  
Sst Variability ◽  
Underlying Surface Conditions ◽  
Nwp Model

AbstractRadar ducting is caused by sharp vertical changes in temperature and, especially, water vapor at the top of the atmospheric boundary layer, both of which are sensitive to variations in the underlying surface conditions, local mesoscale weather, and synoptic weather patterns. High-resolution numerical weather prediction (NWP) models offer an alternative to observation to determine boundary layer (BL) structure and to assess the spatial variability of radar ducts. The benefit of using NWP models for simulating ducting conditions very much depends on the initial state of sea surface temperature (SST) and the model spinup time, both of which have a great impact on BL structure. This study investigates the effects of variation of NWP-model initial conditions and simulation length on the accuracy of simulating the atmosphere’s refractive index over the Wallops Island, Virginia, region, which has pronounced SST variability and complex BL structure. The Met Office Unified Model (MetUM) with horizontal resolution of 4 km (4-km model) was used to simulate the atmospheric environment when observations were made during the Wallops-2000 experiment. Sensitivity tests were conducted in terms of the variability of SST and model spinup time. The evaluation of the model results was focused on low-level moisture, temperature, and surface ducting characteristics including the frequency, strength, and the height of the ducting layer. When provided with more accurate SST and adequate simulation length, the MetUM 4-km model demonstrated an improved ability to predict the observed ducting.

A Statistical Study of Process Variables to Optimize a High Speed Curtain Coater: Part I

TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 20-26 ◽  
Author(s):  
PEEYUSH TRIPATHI ◽  
MARGARET JOYCE ◽  
PAUL D. FLEMING ◽  
MASAHIRO SUGIHARA
Keyword(s):  
Boundary Layer ◽  
Experimental Design ◽  
High Speed ◽  
Statistical Study ◽  
Process Variables ◽  
High Speeds ◽  
The Stability ◽  
Air Removal ◽  
Removal System

Using an experimental design approach, researchers altered process parameters and material prop-erties to stabilize the curtain of a pilot curtain coater at high speeds. Part I of this paper identifies the four significant variables that influence curtain stability. The boundary layer air removal system was critical to the stability of the curtain and base sheet roughness was found to be very important. A shear thinning coating rheology and higher curtain heights improved the curtain stability at high speeds. The sizing of the base sheet affected coverage and cur-tain stability because of its effect on base sheet wettability. The role of surfactant was inconclusive. Part II of this paper will report on further optimization of curtain stability with these four variables using a D-optimal partial-facto-rial design.

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