# Copyright (c) 2013-2018 Siphon Contributors.
# Distributed under the terms of the BSD 3-Clause License.
# SPDX-License-Identifier: BSD-3-Clause
"""Read upper air data from the IA State archives."""
from datetime import datetime
import json
import warnings
import numpy as np
import numpy.ma as ma
import pandas as pd
from .._tools import get_wind_components
from ..http_util import HTTPEndPoint
warnings.filterwarnings('ignore', 'Pandas doesn\'t allow columns to be created', UserWarning)
[docs]class IAStateUpperAir(HTTPEndPoint):
"""Download and parse data from the Iowa State's upper air archive."""
[docs] def __init__(self):
"""Set up endpoint."""
super(IAStateUpperAir, self).__init__('http://mesonet.agron.iastate.edu/json')
[docs] @classmethod
def request_data(cls, time, site_id, **kwargs):
"""Retrieve upper air observations from Iowa State's archive for a single station.
Parameters
----------
time : datetime
The date and time of the desired observation.
site_id : str
The three letter ICAO identifier of the station for which data should be
downloaded.
kwargs
Arbitrary keyword arguments to use to initialize source
Returns
-------
:class:`pandas.DataFrame` containing the data
"""
endpoint = cls()
df = endpoint._get_data(time, site_id, None, **kwargs)
return df
[docs] @classmethod
def request_all_data(cls, time, pressure=None, **kwargs):
"""Retrieve upper air observations from Iowa State's archive for all stations.
Parameters
----------
time : datetime
The date and time of the desired observation.
pressure : float, optional
The mandatory pressure level at which to request data (in hPa). If none is given,
all the available data in the profiles is returned.
kwargs
Arbitrary keyword arguments to use to initialize source
Returns
-------
:class:`pandas.DataFrame` containing the data
"""
endpoint = cls()
df = endpoint._get_data(time, None, pressure, **kwargs)
return df
def _get_data(self, time, site_id, pressure=None):
"""Download data from Iowa State's upper air archive.
Parameters
----------
time : datetime
Date and time for which data should be downloaded
site_id : str
Site id for which data should be downloaded
pressure : float, optional
Mandatory pressure level at which to request data (in hPa).
Returns
-------
:class:`pandas.DataFrame` containing the data
"""
json_data = self._get_data_raw(time, site_id, pressure)
data = {}
for profile in json_data['profiles']:
for pt in profile['profile']:
for field in ('drct', 'dwpc', 'hght', 'pres', 'sknt', 'tmpc'):
data.setdefault(field, []).append(np.nan if pt[field] is None
else pt[field])
for field in ('station', 'valid'):
data.setdefault(field, []).append(np.nan if profile[field] is None
else profile[field])
# Make sure that the first entry has a valid temperature and dewpoint
idx = np.argmax(~(np.isnan(data['tmpc']) | np.isnan(data['dwpc'])))
# Stuff data into a pandas dataframe
df = pd.DataFrame()
df['pressure'] = ma.masked_invalid(data['pres'][idx:])
df['height'] = ma.masked_invalid(data['hght'][idx:])
df['temperature'] = ma.masked_invalid(data['tmpc'][idx:])
df['dewpoint'] = ma.masked_invalid(data['dwpc'][idx:])
df['direction'] = ma.masked_invalid(data['drct'][idx:])
df['speed'] = ma.masked_invalid(data['sknt'][idx:])
df['station'] = data['station'][idx:]
df['time'] = [datetime.strptime(valid, '%Y-%m-%dT%H:%M:%SZ')
for valid in data['valid'][idx:]]
# Calculate the u and v winds
df['u_wind'], df['v_wind'] = get_wind_components(df['speed'],
np.deg2rad(df['direction']))
# Drop any rows with all NaN values for T, Td, winds
df = df.dropna(subset=('temperature', 'dewpoint', 'direction', 'speed',
'u_wind', 'v_wind'), how='all').reset_index(drop=True)
# Add unit dictionary
df.units = {'pressure': 'hPa',
'height': 'meter',
'temperature': 'degC',
'dewpoint': 'degC',
'direction': 'degrees',
'speed': 'knot',
'u_wind': 'knot',
'v_wind': 'knot',
'station': None,
'time': None}
return df
def _get_data_raw(self, time, site_id, pressure=None):
r"""Download data from the Iowa State's upper air archive.
Parameters
----------
time : datetime
Date and time for which data should be downloaded
site_id : str
Site id for which data should be downloaded
pressure : float, optional
Mandatory pressure level at which to request data (in hPa).
Returns
-------
list of json data
"""
query = {'ts': time.strftime('%Y%m%d%H00')}
if site_id is not None:
query['station'] = site_id
if pressure is not None:
query['pressure'] = pressure
resp = self.get_path('raob.py', query)
json_data = json.loads(resp.text)
# See if the return is valid, but has no data
if not (json_data['profiles'] and json_data['profiles'][0]['profile']):
message = 'No data available '
if time is not None:
message += 'for {time:%Y-%m-%d %HZ} '.format(time=time)
if site_id is not None:
message += 'for station {stid}'.format(stid=site_id)
if pressure is not None:
message += 'for pressure {pres}'.format(pres=pressure)
message = message[:-1] + '.'
raise ValueError(message)
return json_data