#!/usr/bin/env python
# Wenchang Yang (wenchang@princeton.edu)
# Wed Mar 11 02:00:36 PM EDT 2026
#windspharm package: https://ajdawson.github.io/windspharm/api/windspharm.xarray.html
if __name__ == '__main__':
    import sys,os
    try:
        from misc.timer import Timer
        tt = Timer(f'[{os.getcwd()}] start ' + ' '.join(sys.argv))
    except:
        pass
import sys, os.path, os, glob, datetime
import xarray as xr, numpy as np, pandas as pd, matplotlib.pyplot as plt
#more imports
wython = '/tigress/wenchang/wython'
if wython not in sys.path: sys.path.append(wython); print('added to python path:', wython)
from misc import get_kws_from_argv
from windspharm.xarray import VectorWind
#
if __name__ == '__main__':
    try:
        tt.check('end import')
    except:
        pass
#
#start from here
year_mon = get_kws_from_argv('year_mon', '2020-07')
ifile = '/projects/w/wenchang/data/era5/analysis_wy/plevels/u200/daily/era5.u200.daily.2020-07.nc'
ifile = ifile.replace('2020-07', f'{year_mon}')
u = xr.open_dataarray(ifile).load().mean('time')
ifile = '/projects/w/wenchang/data/era5/analysis_wy/plevels/v200/daily/era5.v200.daily.2020-07.nc'
ifile = ifile.replace('2020-07', f'{year_mon}')
v = xr.open_dataarray(ifile).load().mean('time')
skiplon, skiplat = 50,25 #reduce dim size by skipping data points for better visualization of quiver plot
ds = xr.Dataset(dict(u=u[::skiplat, ::skiplon], v=v[::skiplat, ::skiplon]))
w = VectorWind(u,v)
speed = w.magnitude()
st = w.streamfunction()
vp = w.velocitypotential()
vort = w.vorticity()
div = w.divergence()
 
 
if __name__ == '__main__':
    from wyconfig import * #my plot settings
    from geoplots import mapplot
    fig,ax = plt.subplots()
    speed.plot()
    ds.plot.quiver(x='longitude', y='latitude', u='u', v='v')
    plt.sca(ax)
    mapplot()
    ax.set_title(f'ERA5 -{year_mon} 200hPa winds vector and speed')
    #savefig
    if 'savefig' in sys.argv or 's' in sys.argv:
        figname = __file__.replace('.py', f'__uv_{year_mon}.png')
        if 'overwritefig' in sys.argv or 'o' in sys.argv:
            wysavefig(figname, overwritefig=True)
        else:
            wysavefig(figname)

    fig,ax = plt.subplots()
    st.plot.contour(levels=21, colors='k')
    vort.plot(robust=True)
    plt.sca(ax)
    mapplot()
    ax.set_title(f'ERA5 {year_mon} 200hPa stream function and relative vorticity')
    #savefig
    if 'savefig' in sys.argv or 's' in sys.argv:
        figname = __file__.replace('.py', f'__psizeta_{year_mon}.png')
        if 'overwritefig' in sys.argv or 'o' in sys.argv:
            wysavefig(figname, overwritefig=True)
        else:
            wysavefig(figname)

    fig, ax = plt.subplots()
    vp.plot.contour(levels=11, colors='k')
    div.plot(robust=True)
    plt.sca(ax)
    mapplot()
    ax.set_title(f'ERA5 {year_mon} 200hPa velocity potential and divergence')
    #savefig
    if 'savefig' in sys.argv or 's' in sys.argv:
        figname = __file__.replace('.py', f'__phidiv_{year_mon}.png')
        if 'overwritefig' in sys.argv or 'o' in sys.argv:
            wysavefig(figname, overwritefig=True)
        else:
            wysavefig(figname)
 
    try:
        tt.check(f'**Done**')
    except:
        pass
    print()
    if 'notshowfig' in sys.argv or 'n' in sys.argv:
        pass
    else:
        if 'plt' in globals(): plt.show()