计算流函数和速度势

MeteoInfo

参考了 MIT 的 Kirill Pankratov 博士1994年的MATLAB程序，在MeteoInfoLab的meteolib包中实现了flowfun函数来计算流场的流函数和速度势，具体可以参考此网页：http://www-pord.ucsd.edu/matlab/stream.htm。

网上例子的实现：

1. e = 2.; g = 1.
   
2. x, y = meshgrid(arange(0, 21), arange(0, 16))  # This makes regular grid
   
3. u = e*x-g*y                  # Linear velocity field
   
4. v = g*x-e*y
   
5. psi, phi = meteolib.flowfun(u, v)  # Here comes the streamfun and potential.
   
6. 
   
7. contour(phi, 20, colors='r', linestyle='--')   # Contours of potential
   
8. contour(psi, 20, colors='g')    # Contours of streamfunction
   
9. quiver(u, v, color='b', size=6)      # Now superimpose the velocity field

e = 2.; g = 1.<br /> x, y = meshgrid(arange(0, 21), arange(0, 16))  # This makes regular grid<br /> u = e*x-g*y                  # Linear velocity field<br /> v = g*x-e*y<br /> psi, phi = meteolib.flowfun(u, v)  # Here comes the streamfun and potential.<br /> <br /> contour(phi, 20, colors='r', linestyle='--')   # Contours of potential<br /> contour(psi, 20, colors='g')    # Contours of streamfunction<br /> quiver(u, v, color='b', size=6)      # Now superimpose the velocity field

一个实际气象风场数据的例子：

1. fn = 'D:/Temp/nc/_grib2netcdf-webmars-public-svc-green-003-6fe5cac1a363ec1525f54343b6cc9fd8-VvjKkH.nc'
   
2. f = addfile(fn)
   
3. u = f['u'][0,'10:55','70:140']
   
4. v = f['v'][0,'10:55','70:140']
   
5. lon = u.dimvalue(1)
   
6. lat = u.dimvalue(0)
   
7. psi, phi = meteo.flowfun(u, v)  # Here comes the streamfunction and potential.
   
8. 
   
9. axesm()
   
10. geoshow('country')
    
11. layer = contour(lon, lat, psi, 20)   # Contours of streamfunction
    
12. s = 3
    
13. quiver(lon[::s], lat[::s], u[::s,::s], v[::s,::s], color='b', size=20)      # Now superimpose the velocity field
    
14. colorbar(layer)

fn = 'D:/Temp/nc/_grib2netcdf-webmars-public-svc-green-003-6fe5cac1a363ec1525f54343b6cc9fd8-VvjKkH.nc'<br /> f = addfile(fn)<br /> u = f['u'][0,'10:55','70:140']<br /> v = f['v'][0,'10:55','70:140']<br /> lon = u.dimvalue(1)<br /> lat = u.dimvalue(0)<br /> psi, phi = meteo.flowfun(u, v)  # Here comes the streamfunction and potential.<br /> <br /> axesm()<br /> geoshow('country')<br /> layer = contour(lon, lat, psi, 20)   # Contours of streamfunction<br /> s = 3<br /> quiver(lon[::s], lat[::s], u[::s,::s], v[::s,::s], color='b', size=20)      # Now superimpose the velocity field<br /> colorbar(layer)

常山赵子龙

matlab的程序在哪里可以下载啊？谢谢

常山赵子龙

早起眼睛不好，看到了，哭

haochizhenhaoch

请问Kirill Pankratov的matlab程序经以下积分后，psi是否消除？
cx = cumsimp(u(1,:));  % Compute x-integration constant
cy = cumsimp(v(:,1));  % Compute y-integration constant
phi = cumsimp(v)+cx(ones(ly,1),:);
phi = (phi+cumsimp(u')'+cy(:,ones(1,lx)))/2;