SPEI - Error

[Bjrj92]

@monocongo As per your recommendation, I have used nco commands to reorient the nc file format in (lat,lon,time). The reoriented data was used to calculate spi and PET. It works fine.
While calculating SPEI, the following error occurs.

process_climate_indices --index spei --periodicity monthly --netcdf_precip TN_Prcp.nc --var_name_precip prcp --netcdf_pet TN_Pet.nc --var_name_pet pet --output_file_base /Documents/Drought/ET_ESTIMATION/PET/SPEI/SPEI-1/TN_SPEI --scales 9 18 --calibration_start_year 1961 --calibration_end_year 2020 --multiprocessing all

ERROR Unable to calculate Pearson Type III parameters due to invalid L-moments
2022-08-04 12:38:15 ERROR Failed to complete
multiprocessing.pool.RemoteTraceback:
"""
Traceback (most recent call last):
File "/home/balaji/anaconda3/lib/python3.9/multiprocessing/pool.py", line 125, in worker
result = (True, func(*args, **kwds))
File "/home/balaji/anaconda3/lib/python3.9/multiprocessing/pool.py", line 48, in mapstar
return list(map(*args))
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/main.py", line 1401, in _apply_along_axis_double
computed_array[i, j] = func1d(x[j], y[j], parameters=params["args"])
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/main.py", line 1124, in _spei
return indices.spei(precips_mm=precips,
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/compute.py", line 549, in transform_fitted_pearson
pearson_parameters(
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/lmoments.py", line 30, in fit
raise ValueError(message)
ValueError: Unable to calculate Pearson Type III parameters due to invalid L-moments
"""

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/main.py", line 1753, in main
_compute_write_index(kwrgs)
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/main.py", line 1021, in _compute_write_index
_parallel_process(keyword_arguments["index"],
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/main.py", line 1297, in _parallel_process
pool.map(_apply_along_axis_double, chunk_params)
File "/home/balaji/anaconda3/lib/python3.9/multiprocessing/pool.py", line 364, in map
return self._map_async(func, iterable, mapstar, chunksize).get()
File "/home/balaji/anaconda3/lib/python3.9/multiprocessing/pool.py", line 771, in get
raise self._value
File "/home/balaji/anaconda3/lib/python3.9/multiprocessing/pool.py", line 125, in worker
result = (True, func(*args, **kwds))
File "/home/balaji/anaconda3/lib/python3.9/multiprocessing/pool.py", line 48, in mapstar
return list(map(*args))
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/main.py", line 1401, in _apply_along_axis_double
computed_array[i, j] = func1d(x[j], y[j], parameters=params["args"])
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/main.py", line 1124, in _spei
return indices.spei(precips_mm=precips,
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/compute.py", line 549, in transform_fitted_pearson
pearson_parameters(
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/lmoments.py", line 30, in fit
raise ValueError(message)
ValueError: Unable to calculate Pearson Type III parameters due to invalid L-moments
multiprocessing.pool.RemoteTraceback:
"""
Traceback (most recent call last):
File "/home/balaji/anaconda3/lib/python3.9/multiprocessing/pool.py", line 125, in worker
result = (True, func(*args, **kwds))
File "/home/balaji/anaconda3/lib/python3.9/multiprocessing/pool.py", line 48, in mapstar
return list(map(*args))
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/main.py", line 1401, in _apply_along_axis_double
computed_array[i, j] = func1d(x[j], y[j], parameters=params["args"])
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/main.py", line 1124, in _spei
return indices.spei(precips_mm=precips,
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/compute.py", line 549, in transform_fitted_pearson
pearson_parameters(
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/lmoments.py", line 30, in fit
raise ValueError(message)
ValueError: Unable to calculate Pearson Type III parameters due to invalid L-moments
"""

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
File "/home/balaji/anaconda3/bin/process_climate_indices", line 8, in
sys.exit(main())
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/main.py", line 1753, in main
_compute_write_index(kwrgs)
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/main.py", line 1021, in _compute_write_index
_parallel_process(keyword_arguments["index"],
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/main.py", line 1297, in _parallel_process
pool.map(_apply_along_axis_double, chunk_params)
File "/home/balaji/anaconda3/lib/python3.9/multiprocessing/pool.py", line 364, in map
return self._map_async(func, iterable, mapstar, chunksize).get()
File "/home/balaji/anaconda3/lib/python3.9/multiprocessing/pool.py", line 771, in get
raise self._value
File "/home/balaji/anaconda3/lib/python3.9/multiprocessing/pool.py", line 125, in worker
result = (True, func(*args, **kwds))
File "/home/balaji/anaconda3/lib/python3.9/multiprocessing/pool.py", line 48, in mapstar
return list(map(*args))
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/main.py", line 1401, in _apply_along_axis_double
computed_array[i, j] = func1d(x[j], y[j], parameters=params["args"])
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/main.py", line 1124, in _spei
return indices.spei(precips_mm=precips,
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/compute.py", line 549, in transform_fitted_pearson
pearson_parameters(
File "/home/balaji/anaconda3/lib/python3.9/site-packages/climate_indices/lmoments.py", line 30, in fit
raise ValueError(message)
ValueError: Unable to calculate Pearson Type III parameters due to invalid L-moments

I Have attached nc files for your reference. kindly help me with this
File_nc.zip

[monocongo]

One suggestion is to examine your precipitation and temperature data to make sure that there are no negative values, all values within a normal range, no missing values, etc. The Pearson III calculation is sensitive to bad data, I've seen this message countless times and it often comes down to a need to clean the data more thoroughly.