http://weather.uwyo.edu/upperair/sounding.html
のための

大気安定度指標


SHOW シュワルター安定指数 -3以下なら雷雨

LIFT 地面付近の状態を考慮。極端に不安定<-9 <非常に不安定< -6 < 激しい雷雨の可能性<-3 <雷雨の可能性 <0<安定

KINX Kインデックス 700hPaの横からの空気の取り込みを考慮。熱雷の予測に適。なし<15 40>100%発雷 850ー500+露点850ー湿数700

TOTAL トータルトータルインデックス 気温減率+下層の湿潤度 44<孤立した弱い雷雨 50<散発的な激しい雷雨 60<広域で並・散発的で激しい雷雨

CAPE 対流有効位置エネルギー LFCTとEQLVの面積、空気塊の浮力、積雲対流が発達しやすい指標。
安定<0 やや不安定<1000 中程度に不安定<2500 非常に不安定<3500<極端に不安定 ただし日本では午前中の計測のため、CAPEが大きくなる午後の値は出ない

CINS 対流抑制 地上からLCLP,LFCTの面積。大きいほど対流起きにくい。CAPEとの差異で潜在不安定の程度がわかる。CAPE>CIN:真性潜在、CAPE<CIN:偽潜在
EQLV 平衡高度 空気塊と周囲の気温が同じ。浮力がなくなる。積乱雲なら7000m・400hPaよる上で発雷
LFCT 自由対流高度 大気が条件付き不安定だとできる。ここより上は絶対不安定で気塊は飽和し自ら上昇 ここに達するには強制上昇が必要
BRCH バルクリチャードソン数 CAPEの大きさと0-6kmの鉛直ウインドシアによる。10-50ならスーパーセル(大きなウインドシア)、35-50ならマルチセル(並みのウインドシア)
LCLP 持上げ凝結高度 雲底高度

PWAT 可降水量mm。地上から大気上端までの気柱に含まれる水蒸気量。地球平均は30mm.降雨の極大に先立って、その場所での可降水量が極大になる。

気温減率 湿潤断熱線より右なら安定、平行なら相当温位の鉛直傾度が0に近い積雲対流が盛ん、左なら条件付き不安定で雷雲発生。
     乾燥断熱線と平行なら、乾燥している=下降流。温位変化なし
     乾燥断熱線より左なら、絶対不安定。地表付近のみ
     



定義と計算式


Sounding Station Parameters and Indices
SLAT Station latitude in degrees
SLON Station longitude in degrees; West longitude is negative
SELV Station elevation in meters
SHOW Showalter index
SHOW = T500 - Tparcel
T500 = Temperature in Celsius at 500 mb
Tparcel = Temperature in Celsius at 500 mb of a parcel lifted from 850 mb
LIFT Lifted index
LIFT = T500 - Tparcel
T500 = temperature in Celsius of the environment at 500 mb
Tparcel = 500 mb temperature in Celsius of a lifted parcel with the average pressure, temperature, and dewpoint of the layer 500 m above the surface
LFTV LIFT computed by using virtual temperature.
SWET SWEAT index
SWET = 12 * TD850 + 20 * TERM2 + 2 * SKT850 + SKT500 + SHEAR
TD850 = Dewpoint in Celsius at 850 mb
TERM2 = MAX ( TOTL - 49, 0 )
TOTL = Total totals index
SKT850 = 850 mb wind speed in knots
SKT500 = 500 mb wind speed in knots
SHEAR = 125 * [ SIN ( DIR500 - DIR850 ) + .2 ]
DIR500 = 500 mb wind direction
DIR850 = 850 mb wind direction
KINX K index
KINX = ( T850 - T500 ) + TD850 - ( T700 - TD700 )
T850 = Temperature in Celsius at 850 mb
T500 = Temperature in Celsius at 500 mb
TD850 = Dewpoint in Celsius at 850 mb
T700 = Temperature in Celsius at 700 mb
TD700 = Dewpoint in Celsius at 700 mb
CTOT Cross Totals index
CTOT = TD850 - T500
TD850 = Dewpoint in Celsius at 850 mb
T500 = Temperature in Celsius at 500 mb
VTOT Vertical Totals index
VTOT = T850 - T500
T850 = Temperature in Celsius at 850 mb
T500 = Temperature in Celsius at 500 mb
TOTL Total Totals index
TOTL = ( T850 - T500 ) + ( TD850 - T500 )
T850 = Temperature in Celsius at 850 mb
TD850 = Dewpoint in Celsius at 850 mb
T500 = Temperature in Celsius at 500 mb
CAPE Convective Available Potential Energy (J/kg)
CAPE = GRAVTY * SUMP ( DELZ * ( TP - TE ) / TE )
SUMP = sum over sounding layers from LFCT to EQLV for which ( TP - TE ) is greater than zero
DELZ = incremental depth
TP = temperature of a parcel from the lowest 500 m of the atmosphere, raised dry adiabatically to the LCL and moist adiabatically thereafter
TE = temperature of the environment
CAPV CAPE computed by using virtual temperature.
CAPV = GRAVTY * SUMP ( DELZ * ( TVP - TVE ) / TVE )
SUMP = sum over sounding layers from LFCV to EQTV for which ( TVP - TVE ) is greater than zero
DELZ = incremental depth
TVP = virtual temperature. of a parcel from the lowest 500 m of the atmosphere, raised dry adiabatically to the LCL and moist adiabatically thereafter
TVE = virtual temperature. of the environment
CINS Convective Inhibition (J/kg)
CINS = GRAVTY * SUMN ( DELZ * ( TP - TE ) / TE )
SUMN = sum over sounding layers from top of the mixed layer to LFCT for which ( TP - TE ) is less than zero.
DELZ = incremental depth
TP = temperature of a parcel from the lowest 500 m of the atmosphere, raised dry adiabatically to the LCL and moist adiabatically thereafter
TE = temperature of the environment
CINV CINS computed by using virtual temperature.
CINV = GRAVTY * SUMN ( DELZ * ( TVP - TVE ) / TVE )
SUMN = sum over sounding layers from top of the mixed layer to LFCV for which ( TVP - TVE ) is less than zero.
DELZ = incremental depth
TVP = virtual temperature. of a parcel from the lowest 500 m of the atmosphere, raised dry adiabatically to the LCL and moist adiabatically thereafter
TVE = virtual temperature. of the environment
EQLV Equilibrium level (hPa)
EQLV = level at which a parcel from the lowest 500 m of the atmosphere is raised dry adiabatically to the LCL and moist adiabatically to a level above which the temperature of the parcel is the same as the environment. If more than one Equilibrium Level exists, the highest one is chosen.
EQTV EQLV computed by using virtual temperature.
LFCT Level of Free Convection (hPa) by comparing temperature between a parcel and the environment
LFCT = level at which a parcel from the lowest 500 m of the atmosphere is raised dry adiabatically to LCL and moist adiabatically to the level above which the parcel is positively buoyant. If more than one LFCT exists, the lowest level is chosen. If the parcel is positively bouyant throughout the sounding, the LFCT is set to be the same as the LCLP.
LFCV LFCT computed by using virtual temperature.
BRCH Bulk Richardson number
BRCH = CAPE / ( 0.5 * U**2 )
CAPE = Convective Available Potential Energy
U = magnitude of shear ( u2 - u1, v2 - v1 )
u1,v1 = average u,v in the lowest 500 m
u2,v2 = average u,v in the lowest 6000 m
BRCV BRCH computed by using CAPV
BRCV = CAPV / ( 0.5 * U**2 )
CAPV = CAPE computed by using virtual temperature.
U = magnitude of shear ( u2 - u1, v2 - v1 )
u1,v1 = average u,v in the lowest 500 m
u2,v2 = average u,v in the lowest 6000 m
LCLT Temperature (K) at the LCL, lifted condensation level, from an average of the lowest 500 meters.
LCLT = [1 / ( 1 / ( DWPK - 56 ) + LN ( TMPK / DWPK ) / 800 )] + 56
LCLP Pressure (hPa) at the LCL, lifted condensation level, from an average of the lowest 500 meters.
LCLP = PRES * ( LCLT / ( TMPC + 273.15 ) ) ** ( 1 / KAPPA )
Poisson's equation
MLTH Mean mixed layer THTA (K)
MLTH = average THTA in the lowest 500 m
MLMR Mean mixed layer MIXR (g/kg)
MLMR = average MIXR in the lowest 500 m
THTK 1000 mb to 500 mb thickness (meter)
THTK = ( Z500 - Z1000 )
Z500 = Height of the 500 mb surface
Z1000 = Height of the 1000 mb surface
PWAT Precipitable water (mm) for the entire sounding