Dr. Kuang's Utilities

wrf-python getvar

 
  • Aug 11, 2022
  • views
>

變數定義

  • wrf-python最強項的功能除了繪圖之外，就屬getvar函數及其內插程式。
  • 引數：(wrfin, varname, timeidx=0, method='cat', squeeze=True, cache=None, meta=True, **kwargs)
    • wrfin: wrf檔案名稱。以netCDF4.Dataset()開啟。
    • varnam: wrf-python使用的變數名稱(詳下表)，不是wrfout檔案的變數名稱。為區別二者，前者用小寫，後者在ncf檔案中是大寫。
    • timeidx: 時間序，0～nt-1
    • method: 時間軸是否壓縮。'cat':保持時間軸（內設）；'join':聯合(壓縮)時間軸
    • squeeze: 如維度僅有一層在輸出矩陣的shape中是否予以去除？內設為True。
    • cache: 將程式中反覆使用的變數暫存成矩陣名稱（varnam:ndarray），以避免反覆讀取、增加執行效能，內設為None。
    • meta: 是否附帶數據的重要資訊（如座標等）。內設是True。
    • Additional Keyword Arguments: 每個變數不太相同，詳下列表格。
      • 如果只有一種單位，就不能使用units選項。
  • 輸出
    • getvar會按照新變數定義的意義輸出成帶座標系統(meta)的矩陣。
  • 原表格按照字母順序排列，以下按照變數類別分類。

Dimensions and Terran

lat, lon, time

Variable Name Description Available Units Additional Keyword Arguments
lat Latitude decimal degrees  
lon Longitude decimal degrees  
times Times in the File or Sequence    
xtimes

XTIME Coordinate

(if applicable)

minutes since

start of

model run

  

Height

Variable Name Description Available Units Additional Keyword Arguments
ter Model Terrain Height

m

km

dm

ft

mi

 units (str) : Set to desired units. Default is ‘m’.
z/height Model Height for Mass Grid

m

km

dm

ft

mi

msl (boolean): Set to False to return AGL values. True is for MSL. Default is True.

units (str) : Set to desired units. Default is ‘m’.
height_agl Model Height for Mass Grid (AGL)

m

km

dm

ft

mi

 units (str) : Set to desired units. Default is ‘m’.
zstag Model Height for Vertically Staggered Grid

m

km

dm

ft

mi

msl (boolean): Set to False to return AGL values. True is for MSL. Default is True.

units (str) : Set to desired units. Default is ‘m’.

First order physics

Temperatures

Variable Name Description Available Units Additional Keyword Arguments
eth/theta_e Equivalent Potential Temperature

K

degC

degF

 units (str) : Set to desired units. Default is ‘K’.
ctt Cloud Top Temperature

degC

K

degF

fill_nocloud (boolean): Set to True to use fill values for cloud free regions rather than surface temperature. Default is False.

missing (float): The fill value to use when fill_nocloud is True.

opt_thresh (float): The optical depth required to trigger the cloud top temperature calculation. Default is 1.0.

units (str) : Set to desired units. Default is ‘degC’.
T2 2m Temperature K  
td2 2m Dew Point Temperature

degC

K

degF

 units (str) : Set to desired units. Default is ‘degC’.
td Dew Point Temperature

degC

K

degF

 units (str) : Set to desired units. Default is ‘degC’.
tc Temperature in Celsius degC  
th/theta Potential Temperature

K

degC

degF

 units (str) : Set to desired units. Default is ‘K’.
temp Temperature (in specified units)

K

degC

degF

 units (str) : Set to desired units. Default is ‘K’.
tk Temperature in Kelvin K  
tv Virtual Temperature

K

degC

degF

 units (str) : Set to desired units. Default is ‘K’.
twb Wet Bulb Temperature

K

degC

degF

 units (str) : Set to desired units. Default is ‘K’.

Pressures

Variable Name Description Available Units Additional Keyword Arguments
p/pres

Full Model Pressure

(in specified units)

Pa

hPa

mb

torr

mmhg

atm

 units (str) : Set to desired units. Default is ‘Pa’.
pressure Full Model Pressure (hPa) hPa  
slp Sea Level Pressure

hPa

hPa

mb

torr

mmhg

atm

 units (str) : Set to desired units. Default is ‘hPa’.

Second order physics

Velocities

Variable Name Description Available Units Additional Keyword Arguments
omg/omega Omega(wiki, earthscience) Pa s-1  
ua U-component of Wind on Mass Points

m s-1

km h-1

mi h-1

kt

ft s-1

 units (str) : Set to desired units. Default is ‘m s-1’.
va V-component of Wind on Mass Points

m s-1

km h-1

mi h-1

kt

ft s-1

 units (str) : Set to desired units. Default is ‘m s-1’.
wa W-component of Wind on Mass Points

m s-1

km h-1

mi h-1

kt

ft s-1

 units (str) : Set to desired units. Default is ‘m s-1’.
uvmet10

10 m U and V Components of Wind

Rotated to Earth Coordinates

m s-1

km h-1

mi h-1

kt

ft s-1

 units (str) : Set to desired units. Default is ‘m s-1’.
uvmet

U and V Components of Wind

Rotated to Earth Coordinates

m s-1

km h-1

mi h-1

kt

ft s-1

 units (str) : Set to desired units. Default is ‘m s-1’.
wspd_wdir

Wind Speed and Direction (wind_from_direction)

in Grid Coordinates

m s-1

km h-1

mi h-1

kt

ft s-1

 units (str) : Set to desired units. Default is ‘m s-1’.
wspd_wdir10

10m Wind Speed and Direction (wind_from_direction)

in Grid Coordinates

m s-1

km h-1

mi h-1

kt

ft s-1

 units (str) : Set to desired units. Default is ‘m s-1’.
uvmet_wspd_wdir

Wind Speed and Direction (wind_from_direction)

Rotated to Earth Coordinates

m s-1

km h-1

mi h-1

kt

ft s-1

 units (str) : Set to desired units. Default is ‘m s-1’.
uvmet10_wspd_wdir

10m Wind Speed and Direction (wind_from_direction)

Rotated to Earth Coordinates

m s-1

km h-1

mi h-1

kt

ft s-1

 units (str) : Set to desired units. Default is ‘m s-1’.

3rd and more orders physics

Energy

Variable Name Description Available Units Additional Keyword Arguments
cape_2d 2D CAPE, Convective Available Potential Energy, Convective Inhibition, Lifted condensation level, level of free convection (MCAPE/MCIN/LCL/LFC) J kg-1 ; J kg-1 ; m ; m missing (float): Fill value for output only
cape_3d 3D CAPE and CIN (Convective INhibition, wiki) J kg-1 missing (float): Fill value for output only
geopt/geopotential Geopotential for the Mass Grid m2 s-2  
geopt_stag Geopotential for the Vertically Staggered Grid m2 s-2  

High Order Dynamics

Variable Name Description Available Units Additional Keyword Arguments
avo Absolute Vorticity 10-5 s-1  
pvo Potential Vorticity PVU  
helicity Storm Relative Helicity(see ref.) m2 s-2 top (float): The top level for the calculation in meters. Default is 3000.0.
updraft_helicity Updraft Helicity m2 s-2

bottom (float): The bottom level for the calculation in meters. Default is 2000.0.

top (float): The top level for the calculation in meters. Default is 5000.0.

Different Forms of Water

Vapors, Cloudness and Precipitation

Variable Name Description Available Units Additional Keyword Arguments
pw Precipitable Water kg m-2  
rh Relative Humidity %  
rh2 2m Relative Humidity %  
cloudfrac Cloud Fraction %

vert_type (str): The vertical coordinate type for the cloud thresholds. Must be ‘height_agl’, ‘height_msl’, or ‘pres’. Default is ‘height_agl’.

low_thresh (float): The low cloud threshold (meters for ‘height_agl’ and ‘height_msl’, pascals for ‘pres’). Default is 300 m (97000 Pa)

mid_thresh (float): The mid cloud threshold (meters for ‘height_agl’ and ‘height_msl’, pascals for ‘pres’). Default is 2000 m (80000 Pa)

high_thresh (float): The high cloud threshold (meters for ‘height_agl’ and ‘height_msl’, pascals for ‘pres’). Default is 6000 m (45000 Pa)
dbz Reflectivity dBZ

do_variant (boolean): Set to True to enable variant calculation. Default is False.

do_liqskin (boolean): Set to True to enable liquid skin calculation. Default is False.
mdbz Maximum Reflectivity dBZ

do_variant (boolean): Set to True to enable variant calculation. Default is False.

do_liqskin (boolean): Set to True to enable liquid skin calculation. Default is False.
Search