def test_rh_spec_humidity(self):
"""Tests specific humidity -> RH calculation
Starting from an RH, an atmospheric pressure and temperature,
calculate specific humidity. Then check to see if the tested code
can reproduce the RH we started with.
"""
rh = 25 * u.pct
p = 1 * u.bar
t = 25 * u.deg_C
e_sat = vp.calc_vp(t)
w_sat = m.mixing_ratio(e_sat, p)
w = rh * w_sat # get vapor pressure from definition of RH
e = p * w / (m.EPSILON + w) # mixing ratio solved for e
# calculate specific humidity using eq 2.19
q = m.EPSILON * (e / (p - (1 - m.EPSILON) * e))
rh_test = m.calc_rh_spec_humidity(q, p, t)
self.assertTrue(np.abs(rh - rh_test) < 0.1 * u.pct,
msg="test RH: {:3.1} ; calculated RH: {:3.1}".format(
rh, rh_test))
def compute_rh(self) :
"""Compute RH for the current utc day
This calls "next()" on the internal RH object. No need to manage it."""
bufs = self.get_buffer_group()
derived = self.get_derived_buffers()
if "rh" in derived.group :
# one day big
p = bufs.get('PSurf').get_utc_day()
q = bufs.get('Qair').get_utc_day()
t = bufs.get('Tair').get_utc_day()
rh = derived.get('rh')
rh.source = met.calc_rh_spec_humidity(q,p,t)
rh.next()
else :
# 2 days big
p = bufs.get('PSurf').get_buffer()
q = bufs.get('Qair').get_buffer()
t = bufs.get('Tair').get_buffer()
rh = derived.create_computed("rh",met.calc_rh_spec_humidity(q,p,t),
u.pct)
return rh
def compute_rh(self):
"""Compute RH for the current utc day
This calls "next()" on the internal RH object. No need to manage it."""
bufs = self.get_buffer_group()
derived = self.get_derived_buffers()
if "rh" in derived.group:
# one day big
p = bufs.get('PSurf').get_utc_day()
q = bufs.get('Qair').get_utc_day()
t = bufs.get('Tair').get_utc_day()
rh = derived.get('rh')
rh.source = met.calc_rh_spec_humidity(q, p, t)
rh.next()
else:
# 2 days big
p = bufs.get('PSurf').get_buffer()
q = bufs.get('Qair').get_buffer()
t = bufs.get('Tair').get_buffer()
rh = derived.create_computed("rh",
met.calc_rh_spec_humidity(q, p, t),
u.pct)
return rh
def test_rh_spec_humidity(self) :
"""Tests specific humidity -> RH calculation
Starting from an RH, an atmospheric pressure and temperature,
calculate specific humidity. Then check to see if the tested code
can reproduce the RH we started with.
"""
rh = 25 * u.pct
p = 1 * u.bar
t = 25 * u.deg_C
e_sat = vp.calc_vp(t)
w_sat = m.mixing_ratio(e_sat, p)
w = rh * w_sat # get vapor pressure from definition of RH
e = p*w/(m.EPSILON + w) # mixing ratio solved for e
# calculate specific humidity using eq 2.19
q = m.EPSILON * (e/(p-(1-m.EPSILON)*e))
rh_test = m.calc_rh_spec_humidity(q, p, t)
self.assertTrue(np.abs(rh-rh_test) < 0.1 * u.pct,
msg="test RH: {:3.1} ; calculated RH: {:3.1}".format(rh, rh_test))
