From 5222f8b8376b71d45b2c6482fbc8f788cd19807c Mon Sep 17 00:00:00 2001
From: rink <rink@ssec.wisc.edu>
Date: Tue, 22 Sep 2020 13:53:01 -0500
Subject: [PATCH] add press to altitude
---
modules/util/util.py | 53 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 53 insertions(+)
diff --git a/modules/util/util.py b/modules/util/util.py
index 419314fa..9bbb40b3 100644
--- a/modules/util/util.py
+++ b/modules/util/util.py
@@ -1,4 +1,11 @@
import numpy as np
+from metpy.units import units
+from metpy.calc import thickness_hydrostatic
+
+
+class MyGenericException(Exception):
+ def __init__(self, message):
+ self.message = message
def haversine_np(lon1, lat1, lon2, lat2):
@@ -53,3 +60,49 @@ def get_breaks(t, threshold):
idxs = np.nonzero(d > threshold)
return idxs
+
+def pressure_to_altitude(pres, temp, prof_pres, prof_temp, sfc_pres, sfc_temp, sfc_elev):
+ if not np.all(np.diff(prof_pres) > 0):
+ raise MyGenericException("target pressure profile must be monotonic increasing")
+
+ if pres < prof_pres[0]:
+ raise MyGenericException("target pressure less than top of pressure profile")
+
+ if temp is None:
+ temp = np.interp(pres, prof_pres, prof_temp)
+
+ i_top = np.argmax(np.extract(prof_pres <= pres, prof_pres)) + 1
+
+ pres_s = prof_pres.tolist()
+ temp_s = prof_temp.tolist()
+
+ pres_s = [pres] + pres_s[i_top:]
+ temp_s = [temp] + temp_s[i_top:]
+
+ prof_pres = np.array(pres_s)
+ prof_temp = np.array(temp_s)
+
+ i_bot = prof_pres.shape[0] - 1
+
+ if sfc_pres > prof_pres[i_bot]:
+ pres_s = pres_s + [sfc_pres]
+ temp_s = temp_s + [sfc_temp]
+ else:
+ idx = np.argmax(np.extract(prof_pres <= sfc_pres, prof_pres))
+ if sfc_temp is None:
+ sfc_temp = np.interp(sfc_pres, prof_pres, prof_temp)
+ pres_s = prof_pres.tolist()
+ temp_s = prof_temp.tolist()
+ pres_s = pres_s[0:idx] + [sfc_pres]
+ temp_s = temp_s[0:idx] + [sfc_temp]
+
+ prof_pres = np.array(pres_s)
+ prof_temp = np.array(temp_s)
+
+ prof_pres = prof_pres * units.hectopascal
+ prof_temp = prof_temp * units.kelvin
+ sfc_elev = sfc_elev * units.meter
+
+ z = thickness_hydrostatic(prof_pres, prof_temp) + sfc_elev
+
+ return z
\ No newline at end of file
--
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