环境python3.6

```

#!/usr/bin/env python

#阿蒋

import sys, os

import requests

import datetime

def check_file_status(filepath, filesize):

sys.stdout.write('\r')

sys.stdout.flush()

size = int(os.stat(filepath).st_size)

percent_complete = (size/filesize)*100

sys.stdout.write('%.3f %s' % (percent_complete, '% Completed'))

sys.stdout.flush()

url = 'https://rda.ucar.edu/cgi-bin/login'

values = {'email' : '******', 'passwd' : ******, 'action' : 'login'}

# Authenticate

ret = requests.post(url,data=values)

if ret.status_code != 200:

print('Bad Authentication')

print(ret.text)

exit(1)

dspath = 'http://rda.ucar.edu/data/ds083.2/'

stime = datetime.datetime(2020,3,27)

etime = datetime.datetime(2020,3,27)

shour = ['_00','_06','_12','_18']

filelist=[]

while stime <= etime:

for j in range(4):

print ('grib2/'+stime.strftime('%Y')+'/'+stime.strftime('%Y.%m')+'/fnl_'

+stime.strftime('%Y%m%d') + shour[j] + '_00.grib2')

filelist.append('grib2/'+stime.strftime('%Y')+'/'+stime.strftime('%Y.%m')+'/fnl_'

+stime.strftime('%Y%m%d') + shour[j] + '_00.grib2')

stime = stime + datetime.timedelta(days=1)

for file in filelist:

filename=dspath+file

file_base = os.path.basename(file)

print('Downloading',file_base)

req = requests.get(filename, cookies = ret.cookies, allow_redirects=True, stream=True)

filesize = int(req.headers['Content-length'])

with open(file_base, 'wb') as outfile:

chunk_size=1048576

for chunk in req.iter_content(chunk_size=chunk_size):

outfile.write(chunk)

if chunk_size < filesize:

check_file_status(file_base, filesize)

check_file_status(file_base, filesize)

print()

```