我想metpy
使用 ERA5 每小时再分析数据来计算近地表(即 2m)比湿度。我昨天刚刚metpy
通过 pip 在本地安装,所以我假设我的代码是最新的。我的问题是我不断遇到以下错误。
这是我目前的代码:
# import modules
import numpy as np
import xarray as xr
from metpy.units import units
import metpy.calc as mpcalc
# read data
d2m = xr.open_dataset('netcdf/ERA5_dewpt2m_1992.nc')
sp = xr.open_dataset('netcdf/ERA5_pres_1992.nc')
# assign units (approach 1)
#d2m = d2m*units.kelvin
#sp = sp*units.pascal
# assign units (approach 2)
d2m = units.Quantity(d2m, "kelvin")
sp = units.Quantity(sp, "pascal")
# calculate specific humidity
aqh2m = mpcalc.specific_humidity_from_dewpoint(sp, d2m)
如果我忽略“单位”步骤,那么该功能当然会抱怨缺少单位。请注意,我尝试了两种不同的方法来处理上述单位,但它们都不起作用。
如果我尝试这种方法:
# assign units (approach 1)
d2m = d2m*units.kelvin
sp = sp*units.pascal
# calculate specific humidity
aqh2m = mpcalc.specific_humidity_from_dewpoint(sp, d2m)
然后我收到以下错误:
ValueError: This function changed in 1.0--double check that the function is being called properly.
`specific_humidity_from_dewpoint` given arguments with incorrect units: `pressure` requires "[pressure]" but given "none", `dewpoint` requires "[temperature]" but given "none"
Any variable `x` can be assigned a unit as follows:
from metpy.units import units
x = units.Quantity(x, "m/s")
但是,如果我采用错误消息中建议的单元分配方法,即:
# assign units (approach 2)
d2m = units.Quantity(d2m, "kelvin")
sp = units.Quantity(sp, "pascal")
# calculate specific humidity
aqh2m = mpcalc.specific_humidity_from_dewpoint(sp, d2m)
然后我只是收到一条不同的错误消息:
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-4-86573b0b8029> in <module>()
----> 1 d2m = units.Quantity(d2m, "kelvin")
2 sp = units.Quantity(sp, "pascal")
3
4 # calculate specific humidity
5 aqh2m = mpcalc.specific_humidity_from_dewpoint(sp, d2m)
~/.local/lib/python3.6/site-packages/pint/quantity.py in __new__(cls, value, units)
201 def __new__(cls, value, units=None):
202 if is_upcast_type(type(value)):
--> 203 raise TypeError(f"Quantity cannot wrap upcast type {type(value)}")
204 elif units is None:
205 if isinstance(value, str):
TypeError: Quantity cannot wrap upcast type xarray.core.dataset.Dataset
我应该怎么办?我不知道从这里去哪里。您可以提供的任何建议/指导将不胜感激。
仅供参考,这是我的各种模块的版本。我将它们全部列出,因为我不确定metpy
内部用于单位支持的内容:
- 蟒蛇3.6.3
- numpy 1.19.5
- xarray 0.16.2
- 熊猫 1.1.5
- 品脱 0.17
- 狗 1.4.0
- pyproj 3.0.1
- matplotlib 2.1.2
- 特质 4.3.2
- scipy 1.0.0
提前致谢。