Changeset 2466 in lmdz_wrf

Timestamp:

Apr 24, 2019, 4:24:10 PM (7 years ago)

Author:

lfita

Message:

Adding:

• `change_CFRefdate': Change CF-time values with a new reference date

File:

• trunk/tools/generic_tools.py (modified) (2 diffs)

trunk/tools/generic_tools.py

@@ -86 +86 @@
 # chainSnum_levnext: Function to provide the next value for a given level from a chainStrnum hirerarchy of numbers
 # chainSnum_num: Function to pass a `ChainStrNum' string to a number
+# change_CFRefdate: Change CF-time values with a new reference date
 # changedate360: Class to change a date  on a 360 days/yr (or 12 30-days months) calendar
 # check_timestep: Function to check if a time-units are 'timestep' based. If it's the case, transform them
@@ -16236 +16237 @@
 #  'days since 1949-12-01 00:00:00')
 
+def change_CFRefdate(timevals, origcftimeu, newSrefdate='1949-12-01 00:00:00'):
+    """ Change CF-time values with a new reference date
+          python datetime package does not work for dates < 1900
+      timevals: actual CF time-values
+      origcftimeu: current original CF-time units [tunits] since [YYYY]-[MM]-[HH] 
+        [HH]:[MM]:[SS] (or similar)
+      newSrefdate: new CF refDate [YYYY]-[MM]-[HH] [HH]:[MM]:[SS]
+    >>> times = [15.5, 45, 74.5, 105, 135.5, 166, 196.5, 227.5, 258, 288.5, 319]
+    >>> change_CFRefdate(times, '1850-01-01 00:00:00', '1949-12-01 00:00:00')
+    [-36478.5 -36449.  -36419.5 -36389.  -36358.5 -36328.  -36297.5 -36266.5
+      -36236.  -36205.5 -36175. ]
+    """
+    fname = 'change_CFRefedate'
+
+    availtu = ['years', 'weeks', 'days', 'hours', 'minutes', 'seconds']
+
+    # original
+    origtv = origcftimeu.split(' ')
+    origtunits = origtv[0]
+    origSrefdate = origtv[2]
+
+    yrref = int(origSrefdate[0:4])
+    monref = int(origSrefdate[5:7])
+    dayref = int(origSrefdate[8:10])
+
+    if int(yrref) < 1970: origsing = -1.
+    else: origsing = 1.
+
+# Does original reference date contain a time value [YYYY]-[MM]-[DD] [HH]:[MI]:[SS]
+##
+    trefT = origcftimeu.find(':')
+    if not trefT == -1:
+        if len(origtv) == 3:
+            horref=int(origSrefdate[11:13])
+            minref=int(origSrefdate[14:16])
+            secref=int(origSrefdate[17:19])
+        else:
+            origSreftime = origtv[3]
+            horref=int(origSreftime[0:2])
+            minref=int(origSreftime[3:5])
+            secref=int(origSreftime[6:8])
+    else:
+        horref = 0
+        minref = 0
+        secref = 0
+
+    # Transforming to julian days (reference -4712 January 1st 00 UTC)
+    origdays = juliandate(yrref,monref,dayref,horref,minref,secref)
+
+    # new
+    yrnew = int(newSrefdate[0:4])
+    monnew = int(newSrefdate[5:7])
+    daynew = int(newSrefdate[8:10])  
+
+    if int(yrnew) < 1970: newsing = -1.
+    else: newsing = 1.
+
+# Does reference date contain a time value [YYYY]-[MM]-[DD] [HH]:[MI]:[SS]
+##
+    tnewT = newSrefdate.find(':')
+    if not tnewT == -1:
+        hornew=int(newSrefdate[11:13])
+        minnew=int(newSrefdate[14:16])
+        secnew=int(newSrefdate[17:19])
+    else:
+        hornew = 0
+        minnew = 0
+        secnew = 0
+
+    # Transforming to julian days (reference -4712 January 1st 00 UTC)
+    newdays = juliandate(yrnew,monnew,daynew,hornew,minnew,secnew)
+
+    if origtunits == 'years':
+        daysdtr = 365.
+    elif origtunits == 'weeks':
+        daysdtr = 7.
+    elif origtunits == 'days':
+        daysdtr = 1.
+    elif origtunits == 'hours':
+        daysdtr = 1./24.
+    elif origtunits == 'minutes':
+        daysdtr = 1./(24.*60.)
+    elif origtunits == 'seconds':
+        daysdtr = 1./(24.*3600.)
+    else:
+        print errormsg
+        print '  ' + fname + ": original time-units '" + origtunits + "' not ready !!"
+        print '    available ones: ', availtu
+        quit(-1)
+
+    # Seconds difference respect new date
+    daysdiff = origdays - newdays
+
+    if type(timevals) != type(np.ones((2), dtype=int)):
+        newtimevals = np.array(timevals, dtype=np.float64)
+        newtimevals = newtimevals*daysdtr
+    else:
+        newtimevals = timevals*daysdtr
+
+    # Re-scaling to the absolute reference
+    newtimevals = newtimevals + origdays
+
+    # Re-scaling to the CF-time reference
+    newtimevals = newtimevals - newdays
+
+    return newtimevals
+
+times = [15.5, 45, 74.5, 105, 135.5, 166, 196.5, 227.5, 258, 288.5, 319]
+print change_CFRefdate(times, 'days since 1850-01-01 00:00:00', '1949-12-01 00:00:00')
+
 #quit()