气象计算函数
作者Lou Xiao创建时间2023-10-27 16:58:11更新时间2023-10-27 16:58:11
1. 比湿(relative humidity) To 相对湿度(specific humidity)
参考：
1. How do I convert specific humidity to relative humidity?
2. METPY
1.1 精确计算
1.双击鼠标左键复制此行；2.单击复制所有代码。
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import numpy as np
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def relative_humidity_from_specific_humidity(pressure, temperature, specific_humidity):
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# @param pressure: atmosphere pressure, units: Pa
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# @param temperature: atmosphere temperature, units: K
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# @param specific_humidity: specific humidity, units: 1
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# @return: relative_humidity, units: %
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es = 611.2 * np.exp((17.67 * (temperature - 273.15)) / (temperature - 29.65))
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ws = 0.6219569100577033 * es / (pressure - es)
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wq = specific_humidity / (1 - specific_humidity)
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rh = 100 * wq / ws
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return rh
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print("relative_humidity:", relative_humidity_from_specific_humidity(
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1013.25 * 100, # as Pa
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30 + 273.15, # as K
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18 / 1000,
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))
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# 67.38936293846538
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# 验证
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from metpy.calc import relative_humidity_from_specific_humidity as metpy_relative_humidity_from_specific_humidity
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from metpy.units import units
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print("relative_humidity:", metpy_relative_humidity_from_specific_humidity(
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1013.25 * units.hPa,
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30 * units.degC,
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18 / 1000
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).to('percent'))
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# 67.3893629384654
1.2 近似计算
1.双击鼠标左键复制此行；2.单击复制所有代码。
1
import numpy as np
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def relative_humidity_from_specific_humidity(pressure, temperature, specific_humidity):
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# @param pressure: atmosphere pressure, units: Pa
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# @param temperature: atmosphere temperature, units: K
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# @param specific_humidity: specific humidity, units: 1
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# @return: relative_humidity, units: %
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es = 611.2 * np.exp((17.67 * (temperature - 273.15)) / (temperature - 29.65))
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ws = 0.622 * es / pressure
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wq = specific_humidity
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rh = 100 * wq / ws
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return rh
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print("relative_humidity:", relative_humidity_from_specific_humidity(
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1013.25 * 100, # as Pa
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30 + 273.15, # as K
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18 / 1000,
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))
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# 69.06566061892872
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# or
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import numpy as np
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def relative_humidity_from_specific_humidity(pressure, temperature, specific_humidity):
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# @param pressure: atmosphere pressure, units: Pa
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# @param temperature: atmosphere temperature, units: K
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# @param specific_humidity: specific humidity, units: 1
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# @return: relative_humidity, units: %
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rh = 0.263 * pressure * specific_humidity / np.exp((17.67 * (temperature - 273.15)) / (temperature - 29.65))
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return rh
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print("relative_humidity:", relative_humidity_from_specific_humidity(
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1013.25 * 100, # as Pa
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30 + 273.15, # as K
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18 / 1000,
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))
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# 69.05444656574537
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