Coverage for src / CSET / operators / temperature.py: 0%

1# © Crown copyright, Met Office (2022-2026) and CSET contributors. 

2# 

3# Licensed under the Apache License, Version 2.0 (the "License"); 

4# you may not use this file except in compliance with the License. 

5# You may obtain a copy of the License at 

6# 

7# http://www.apache.org/licenses/LICENSE-2.0 

8# 

9# Unless required by applicable law or agreed to in writing, software 

10# distributed under the License is distributed on an "AS IS" BASIS, 

11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 

12# See the License for the specific language governing permissions and 

13# limitations under the License. 

14 

15"""Operators for temperature conversions.""" 

16 

17import iris.cube 

18import numpy as np 

19 

20from CSET._common import iter_maybe 

21from CSET.operators.constants import EPSILON, T0 

22from CSET.operators.pressure import vapour_pressure 

23 

24 

25def dewpoint_temperature( 

26 temperature: iris.cube.Cube | iris.cube.CubeList, 

27 relative_humidity: iris.cube.Cube | iris.cube.CubeList, 

28) -> iris.cube.Cube | iris.cube.CubeList: 

29 """Calculate the dewpoint temperature.""" 

30 Td = iris.cube.CubeList([]) 

31 for T, RH in zip( 

32 iter_maybe(temperature), iter_maybe(relative_humidity), strict=True 

33 ): 

34 vp = vapour_pressure(T, RH) 

35 td = vp.copy() 

36 td.data = (243.5 * np.log(vp.core_data()) - 440.8) / ( 

37 19.48 - np.log(vp.core_data()) 

38 ) 

39 td.data[td.data - T0 < -35.0] = np.nan 

40 td.data[td.data - T0 > 35.0] = np.nan 

41 td.units("K") 

42 td.rename("dewpoint temperature") 

43 Td.append(td) 

44 if len(Td) == 1: 

45 return Td[0] 

46 else: 

47 return Td 

48 

49 

50def virtual_temperature( 

51 temperature: iris.cube.Cube | iris.cube.CubeList, 

52 mixing_ratio: iris.cube.Cube | iris.cube.CubeList, 

53) -> iris.cube.Cube | iris.cube.CubeList: 

54 """Calculate the virtual temperature.""" 

55 Tv = iris.cube.CubeList([]) 

56 for T, W in zip(iter_maybe(temperature), iter_maybe(mixing_ratio), strict=True): 

57 virT = T * ((W + EPSILON) / (EPSILON * (1 + W))) 

58 virT.rename("virtual_temperature") 

59 Tv.append(virT) 

60 if len(Tv) == 1: 

61 return Tv[0] 

62 else: 

63 return Tv