study of the relationship between ice phase and cloud-top … · 2016-07-29 · study of the...
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Stud
y of
the
rela
tions
hip
betw
een
ice
phas
e an
d cl
oud-
top
tem
pera
ture
with
MO
DIS
dat
aC
athe
rine
Nau
dan
d A
ntho
ny D
el G
enio
, GIS
S, N
Y
Abs
trac
t: C
loud
feed
back
in G
CM
clim
ate
chan
ge si
mul
atio
ns is
sens
itive
topr
edic
tions
of c
loud
pha
se b
ecau
se o
f the
diff
eren
t mic
roph
ysic
al a
nd ra
diat
ive
prop
ertie
s of l
iqui
d an
d ic
e. U
sual
ly th
e liq
uid-
ice
trans
ition
is p
aram
eter
ized
as a
sim
ple
func
tion
of te
mpe
ratu
re, b
ut ic
e oc
curr
ence
in c
loud
s is k
now
n to
dep
end
on th
e un
derly
ing
dyna
mic
s of t
he c
loud
syst
em.
We
are
usin
g M
OD
IS d
ata
to g
ain
insi
ghts
into
this
beh
avio
ur th
at m
ight
serv
e as
a g
uide
to im
prov
ed p
aram
eter
izat
ions
. C
loud
top
tem
pera
ture
s wer
e ob
tain
ed fr
om5-
min
leve
l 2 M
OD
IS T
ERR
A a
nd A
QU
A d
ay-ti
me
gran
ules
, alo
ng w
ith S
WIR
pha
se fo
r all
avai
labl
e w
inte
rs (D
ec-J
an-F
eb)f
rom
the
star
t of t
he m
issi
ons u
ntil
Febr
uary
200
4. C
loud
y pi
xels
in e
ach
gran
ules
wer
e se
lect
ed o
ver t
he n
orth
ern
parts
of t
he A
tlant
ic a
nd P
acifi
c oc
eans
in th
e ar
ea c
over
ed b
y th
e st
orm
trac
ks a
nd a
ggre
gate
d in
2x2
.5°
grid
box
es. F
or e
ach
grid
box
, all
pixe
ls id
entif
ied
as ic
e on
ly a
nd ic
e or
wat
er a
re se
lect
ed a
nd so
rted
into
tem
pera
ture
bin
s def
ined
eve
ry 2
K fr
om 2
00 to
300
K. H
isto
gram
s can
then
be
obta
ined
that
giv
e th
e fr
actio
n of
ice
clou
d pi
xels
ove
r the
tota
l num
ber o
f ice
and
wat
er c
loud
pix
els i
n a
give
n te
mpe
ratu
re ra
nge.
The
grid
boxe
s are
furth
er
aggr
egat
ed a
long
the
best
est
imat
e of
the
stor
m tr
ack
traje
ctor
yob
tain
ed fr
om a
con
tem
pora
ry N
CEP
rean
alys
is st
orm
trac
k at
las (
Cha
ndle
r and
Jona
s, 19
99) a
nd d
ivid
ed in
to a
wes
t, ce
ntra
l and
eas
t reg
ion.
The
stor
m tr
ajec
torie
s are
cho
sen
so th
at th
e st
orm
freq
uenc
y of
occ
urre
nce
does
not
var
y m
uch
over
the
traje
ctor
y. H
owev
er, w
e fin
d th
at b
oth
mea
n in
tens
ity (c
entra
l pre
ssur
e) a
nd se
verit
y (p
eak
inte
nsity
) inc
reas
e al
ong
the
track
.
Atla
ntic
oce
an
NC
EP st
orm
freq
uenc
y (%
) for
all
win
ters
from
Dec
embe
r 200
0 to
Fe
brua
ry 2
004.
NC
EP st
orm
mea
n in
tens
ity (m
b)
for a
ll w
inte
rs fr
om D
ecem
ber 2
000
to F
ebru
ary
2004
.
NC
EP st
orm
seve
rity
(mb)
for a
ll w
inte
rs fr
om D
ecem
ber 2
000
to
Febr
uary
200
4.
MO
DIS
ice
clou
d fr
actio
n ve
rsus
clo
ud-
top
tem
pera
ture
for a
ll m
onth
s and
bot
h pl
atfo
rms a
ccum
ulat
ed in
the
wes
tern
(s
olid
), ce
ntra
l (da
shed
) and
eas
tern
(dot
-da
sh) p
ortio
ns o
f the
stor
m tr
ack.
Ther
e ar
e at
leas
t 10,
000
pixe
ls in
eac
h 2K
te
mpe
ratu
re ra
nge.
NC
EP st
orm
freq
uenc
y (%
) for
all
win
ters
from
Dec
embe
r 200
0 to
Fe
brua
ry 2
004.
NC
EP st
orm
mea
n in
tens
ity (m
b)
for a
ll w
inte
rs fr
om D
ecem
ber 2
000
to F
ebru
ary
2004
.
NC
EP st
orm
seve
rity
(mb)
for a
ll w
inte
rs fr
om D
ecem
ber 2
000
to
Febr
uary
200
4.
For 4
diff
eren
t tem
pera
ture
rang
es, i
ce
clou
d fr
actio
n ve
rsus
stor
m fr
eque
ncy
(top)
, mea
n in
tens
ity (c
entra
l) an
d se
verit
y (b
otto
m).
The
rang
es a
re: 2
30-
240K
(col
umn
1), 2
40-2
50K
(col
umn
2), 2
50-2
60K
(col
umn
3) a
nd 2
60-
270K
(col
umn
4).
Var
iatio
ns a
long
the
estim
ated
stor
m
mea
n tra
ject
ory
of st
orm
freq
uenc
y (to
p), m
ean
inte
nsity
(cen
tre) a
nd
seve
rity
(bot
tom
) as t
he st
orm
s mov
e ea
stw
ard.
Paci
fic O
cean
For 4
diff
eren
t tem
pera
ture
rang
es, i
ce
clou
d fr
actio
n ve
rsus
stor
m fr
eque
ncy
(top)
, mea
n in
tens
ity (c
entra
l) an
d se
verit
y (b
otto
m).
The
rang
es a
re: 2
30-
240K
(col
umn
1), 2
40-2
50K
(col
umn
2), 2
50-2
60K
(col
umn
3) a
nd 2
60-
270K
(col
umn
4).
MO
DIS
ice
clou
d fr
actio
n ve
rsus
clo
ud-
top
tem
pera
ture
for a
ll m
onth
s and
bot
h pl
atfo
rms a
ccum
ulat
ed in
the
wes
tern
(s
olid
), ce
ntra
l (da
shed
) and
eas
tern
(dot
-da
sh) p
ortio
ns o
f the
stor
m tr
ack.
Ther
e ar
e at
leas
t 10,
000
pixe
ls in
eac
h 2K
te
mpe
ratu
re ra
nge.
Var
iatio
ns a
long
the
estim
ated
stor
m
mea
n tra
ject
ory
of st
orm
freq
uenc
y (to
p), m
ean
inte
nsity
(cen
tre) a
nd
seve
rity
(bot
tom
) as t
he st
orm
s mov
e ea
stw
ard.
Prel
imin
ary
Con
clus
ion:
Ove
r the
Atla
ntic
stor
m tr
ack
regi
on, w
e fo
und
that
as t
he c
loud
s mov
e ea
stw
ard,
the
ice
clou
d fr
actio
n at
a g
iven
tem
pera
ture
tend
s to
incr
ease
, im
plyi
ng th
at h
eter
ogen
eous
free
zing
bec
omes
mor
e im
porta
nt a
s the
stor
ms t
rave
l eas
twar
d. F
urth
erm
ore,
ther
e is
aco
rrel
atio
n be
twee
n ic
e cl
oud
frac
tion
and
stor
m in
tens
ity, a
t lea
st fo
r sto
rmsw
ith a
larg
e en
ough
inte
nsity
(pre
ssur
e <
980m
b). A
s st
orm
inte
nsity
incr
ease
s, ic
ecl
oud
frac
tion
incr
ease
s, su
gges
ting
a dy
nam
ic c
ontro
l.
How
ever
, ove
r the
Pac
ific
ocea
n, th
e be
havi
our i
sinv
erte
d: th
e ic
e cl
oud
frac
tion
decr
ease
s as s
torm
s mov
e ea
stw
ard
and
isan
ticor
rela
ted
with
stor
m in
tens
ity, s
ugge
stin
g an
othe
r inf
luen
ce, p
erha
ps v
aryi
ng a
eros
ol c
once
ntra
tion.
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