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Wrong wind direction of vertcross

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评估

难度
4/5
预计耗时
3-5 天
新手友好度
35/100
Issue 类型
缺陷
描述清晰度
基本清楚
活跃度
停滞
技术栈
matplotlib, numpy, python
领域
data-visualization

调研方向

使用 vertcross、interplevel 和 matplotlib.quiver 重现该示例，然后将剖面分量与 15 km 高度的水平风图进行比较。首先检查 vertcross 文档以及任何相关的测试或实现；当解释或纠正方向差异并记录一种经过验证的绘图方法后，即视为完成。

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描述

support

Background

Hi, all,

I'm trying to plot the wind quiver on the crosssection. But, I find the wind direction is wrong. Here're the details.

Read data and vertcross

import numpy as np
from wrf import getvar, interplevel, ALL_TIMES, CoordPair, vertcross, to_np, latlon_coords
from netCDF4 import Dataset
import matplotlib.pyplot as plt

data_dir = '../data/wrfchem/wrfout/20200901/lnox_500/'
file = data_dir+'wrfout_d04_2020-09-01_05:00:00_subset'
ncfile = Dataset(file)

# set cross
start_lon = 118.6
end_lon = 119
start_lat = 32.1
end_lat = 31.7

start_point = CoordPair(lat=start_lat, lon=start_lon)
end_point = CoordPair(lat=end_lat, lon=end_lon)

# get vars
u = getvar(ncfile, 'ua')
v = getvar(ncfile, 'va')
w = getvar(ncfile, 'wa')
wspd = getvar(ncfile, 'uvmet_wspd_wdir')
dbz = getvar(ncfile, 'dbz')
z = getvar(ncfile, 'z', units='km')

# vertcross and subset to 0-17 km
cross_u = vertcross(u, z, wrfin=ncfile, start_point=start_point, end_point=end_point, latlon=True, meta=True).sel(vertical=slice(0, 17))
cross_v = vertcross(v, z, wrfin=ncfile, start_point=start_point, end_point=end_point, latlon=True, meta=True).sel(vertical=slice(0, 17))
cross_w = vertcross(w, z, wrfin=ncfile, start_point=start_point, end_point=end_point, latlon=True, meta=True).sel(vertical=slice(0, 17))
cross_dbz = vertcross(dbz, z, wrfin=ncfile, start_point=start_point, end_point=end_point, latlon=True, meta=True).sel(vertical=slice(0, 17))
cross_wspd = vertcross(wspd, z, wrfin=ncfile, start_point=start_point, end_point=end_point, latlon=True, meta=True).sel(vertical=slice(0, 17))

# get xlabels
coord_pairs = to_np(cross_dbz.coords["xy_loc"])
xticks = np.arange(coord_pairs.shape[0])
xlabels = [pair.latlon_str() for pair in to_np(coord_pairs)]

fig, ax = plt.subplots(figsize=(10, 6))
ax.set_xticks(xticks[::20])
ax.set_xticklabels(['(' +s.replace(',', '\n') + ')' for s in xlabels[::20]], fontsize=4) # rotation

# plot wind
xs = np.arange(0, cross_w.shape[-1], 1)
ys = to_np(cross_w.coords['vertical'])
step = 2

# plot dbz
m = ax.contourf(xs[::step],
                ys[::step],
                to_np(cross_dbz[::step, ::step]),
                cmap='Reds'
               )


q = ax.quiver(xs[::step],
              ys[::step],
              to_np(cross_u[::step, ::step]+cross_v[::step, ::step]),
              to_np(cross_w[::step, ::step])
             )

plt.colorbar(m, label='dBZ')
plt.savefig('./cross.jpg', dpi=300)

Result:
cross

Wind interpolated to 15 km

# Get the lat/lon coordinates
lats, lons = latlon_coords(u)

zlevel = 15  # km
u_zlevel = interplevel(u, z, zlevel)
v_zlevel = interplevel(v, z, zlevel)

step = 10

fig, ax = plt.subplots(figsize=(10, 6))
q = plt.quiver(to_np(lons[::step,::step]), to_np(lats[::step,::step]),
              to_np(u_zlevel[::step, ::step]), to_np(v_zlevel[::step, ::step])
             )

qk = plt.quiverkey(q, 1, 1.05, 10, r'$10 m/s}$', labelpos='E')
plt.plot([start_lon, end_lon], [start_lat, end_lat], '-r')
plt.title('Wind at 15 km level')
plt.savefig('./zlev.jpg', dpi=300)

zlev

Problem

As you can see, the wind at the 15 km level should blow from the start point to the endpoint.
But, the 15 km wind in the crosssection is the opposite.

Is there anything wrong with my method?
Thanks in advance!

主要语言
Python
星标
498
派生
178
30 天内没有已合并 PR

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