Academic Edi o s: Panagio is
T. Nas os and Dio an os
G. Hadjimi sis
Published: 11 Sep embe 2025
Ci a ion: D akaki, E.; Ma inou, E.;
Neh i , A.R.; Ka sa ados, P.; Ami idis,
V. Recons uc ing Saha an
Dus –Cloud Scenes wi h WRF-L:
Ini ial E alua ion o Ae osol-Awa e
Ice Nuclea ion Schemes. En i on.
Ea h Sci. P oc. 2025,35, 21. h ps://
doi.o g/10.3390/eesp2025035021
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P oceeding Pape
Recons uc ing Saha an Dus –Cloud Scenes wi h WRF-L: Ini ial
E alua ion o Ae osol-Awa e Ice Nuclea ion Schemes †
Eleni D akaki 1,2,* , Eleni Ma inou 1, Amin R. Neh i 3, Pe os Ka sa ados 2and Vassilis Ami idis 1
1Na ional Obse a o y o A hens, IAASARS, 15236 A hens, G eece; [email p o ec ed] (E.M.);
[email p o ec ed] (V.A.)
2Geog aphy Depa men , Ha okopio Uni e si y, 17671 A hens, G eece; [email p o ec ed]
3NASA Langley Resea ch Cen e , Hamp on, VA 23681, USA; amin. [email p o ec ed]
*Co espondence: [email p o ec ed]
†P esen ed a he 17 h In e na ional Con e ence on Me eo ology, Clima ology, and A mosphe ic
Physics—COMECAP 2025, Nicosia, Cyp us, 29 Sep embe –1 Oc obe 2025.
Abs ac
This s udy explo es he ole o mine al dus in ice nuclea ion using WRF-L model simu-
la ions du ing he ASKOS-ESA and CPEX-CV campaigns (Cabo Ve de, 2022). Nume ical
expe imen s a e ca ied ou o examine dus impac s and seconda y ice p oduc ion ia
he Halle –Mossop p ocess. The esul s show a iabili y in ice and liquid wa e pa hs,
wi h he modeled ae osol op ical dep h aligning well wi h AERONET da a. A case s udy
o 15 Sep embe 2022 e eals no able cloud s uc u e di e ences in ae osol-awa e simula-
ions. These indings can in o m u u e LES simula ions wi h assimila ed ae osol ields and
ada compa isons, emphasizing he impo ance o accu a ely ep esen ing ae osol–cloud
in e ac ions in a mosphe ic models.
Keywo ds: ice nuclea ion; mine al dus ; cloud o ma ion
1. In oduc ion
Mine al dus ae osols play a c i ical ole in cloud mic ophysics, pa icula ly by ac ing
as ice-nuclea ing pa icles (INPs) in mixed-phase and ci us clouds [
1
]. Thei p esence can
in luence cloud li e ime, adia i e p ope ies, and p ecipi a ion p ocesses, making hem
an impo an componen o wea he and clima e sys ems. Despi e hei signi icance, he
ep esen a ion o dus - ela ed ice nuclea ion in a mosphe ic models emains unce ain,
pa ly due o limi ed obse a ional cons ain s and simpli ied pa ame e iza ions [2].
In his s udy, we use he WRF-L model, a dus -sensi i e e sion o WRF-Chem [
3
], o
simula e cloud scenes obse ed du ing he ASKOS-ESA and CPEX-CV campaigns in Cabo
Ve de (2022) [
4
,
5
]. A new ae osol-awa e ice nuclea ion pa ame e iza ion [
6
] is implemen ed
and e alua ed h ough mesoscale simula ions, aiming o be e cap u e he impac o
Saha an dus on cloud o ma ion and e olu ion.
2. Me hods
We eplaced he empe a u e-dependen ice nuclea ion p ocess in he Mo ison mic o-
physics scheme [
7
,
8
] wi h a new ae osol-awa e pa ame e iza ion based on he ela ionship
p oposed in [
6
]. The Mo ison scheme also includes seconda y ice p oduc ion h ough he
Halle and Mossop p ocess [
9
]. Employing he modi ied Mo ison scheme, we conduc ed
ini ial mesoscale simula ions (15 km
×
15 km esolu ion) wi h he WRF-L model [
3
]. The
model domain was app op ia ely de ined in o de o simula e he Saha an dus emission
En i on. Ea h Sci. P oc. 2025,35, 21 h ps://doi.o g/10.3390/eesp2025035021
En i on. Ea h Sci. P oc. 2025,35, 21 2 o 6
and anspo owa ds he A lan ic Ocean, co e ing he mine al dus sou ces o Saha a and
he cen al A lan ic Ocean.
Me eo ological o cing is p o ided by ECMWF-IFS model eanalysis (ERA5) da ase s,
upda ed e e y 6 h. The comple e con igu a ion op ions o he un a e lis ed in Table 1.
Table 1. Model con igu a ion.
Pa ame e iza ion Scheme Pa ame e iza ion Scheme
Su ace Model Noah [10] s _su ace_physics 2
Su ace Laye MM5 [11] s _s clay_physics 2
Radia ion (SW and LW) RRTMG [12] a_sw(lw)_physics 4
Mic ophysics Mo ison 2-momen [8] mp_physics 10
Cumulus G ell-3 [13] cu_physics 5
Bounda y Laye MYNN 2.5 [14] bl_pbl_physics 5
Chemis y GOCART simple [15,16] chem_op 300
Dus Scheme AFWA [16] dus _op 3
These simula ions we e designed o assess (a) he impac o he new ice nuclea ion
pa ame e iza ion and (b) he e ec o seconda y ice p oduc ion (SIP), inco po a ing he new
ae osol-awa e scheme o p ima y ice nuclea ion. A summa y o hese es s is p esen ed in
Table 2.
Table 2. Model expe imen s pe o med in his s udy using he WRF-L model.
MODEL EXPERIMENTS DUST_IN SIP
NoAERO-NoSIP No No
AERO-NoSIP yes No
AERO-SIP yes Yes
The p ima y goal o hese simula ions was o iden i y cases whe e no able di e ences
a ise om he inclusion o exclusion o speci ic physical p ocesses. Fo hese pu poses, he
liquid wa e pa h and he ice wa e pa h om he model we e calcula ed as he sum o he
in eg al o he concen a ion o all he di e en liquid hyd ome eo s (cloud d ople s and
ain) o all he ice hyd ome eo s (snow, ice, and g aupel), espec i ely. The simula ions
co e ed he pe iod o he CPEX-CV campaign, held du ing Sep embe 2022, a sub-pe iod o
he ASKOS-ESA campaign, du ing which mul iple NASA DC-8 ai c a ligh s ook place.
3. Resul s and Discussion
3.1. Simula ed Ae osol Field
To examine he impac o he indi ec ae osol e ec in he simula ion o a cloud scene
by WRF-L, i is impo an o i s accu a ely simula e he ae osol ields wi hin he domain.
In ou simula ions, he AOD is adequa ely ep esen ed, as shown in Figu e 1, excep o
some days in la e Augus , when he model o e p edic s dus .
Figu e 1. Compa ison o he modeled dus op ical dep h a 550 nm (blue line), colloca ed in ime and
space wi h he AERONET dus -domina ed AOD a 550 nm, om he a ailable s a ions wi hin he
domain (g ay do s).
En i on. Ea h Sci. P oc. 2025,35, 21 3 o 6
3.2. Simula ed LWP and IWP
To iden i y cases o in e es whe e signi ican di e ences be ween model simula-
ions occu , we analyzed he ime se ies o he simula ed LWP and IWP, as shown in
Figu es 2and 3
. Examining he di e ences in he simula ion whe e we applied ei he
he ae osol-awa e scheme o he empe a u e-awa e scheme o p ima y ice o ma ion in
WRF-L (Figu e 2), we ound h ee days whe e he simula ed IWP di e ed signi ican ly
(14, 15, and 30 Sep embe 2022) and six days whe e he LWP di e ed signi ican ly (9, 10,
14, 15, 16, and 30 Sep embe 2022). Fo he expe imen s shown in Figu e 3(i.e., whe e he
dus -awa e pa ame e iza ion is on, and he seconda y ice p oduc ion h ough he Halle
and Mossop p ocess is on/o ), we ound 3 days whe e he IWP di e ed signi ican ly (22,
23, and 29 Sep embe 2022) and se en days whe e he LWP di e ed (9, 10, 14, 20, 26, 29,
and 30 Sep embe 2022).
Figu e 2. Time se ies o he LWP and IWP du ing C-PEX ligh s o expe imen s wi h and wi hou he
dus -awa e ice nuclea ion scheme. Red boxes indica e he days wi h signi ican di e ences be ween
he simula ed Liquid and ice wa e pa h o he di e en expe imen s.
Figu e 3. Simila o Figu e 2 o expe imen s wi h SIP ac i a ed and no ac i a ed.
3.3. Simula ed Cloud Scenes Agains Ai c a Obse a ions
An example o hese days is p esen ed in Figu e 4. In he le column o he igu e,
he simula ed cold cloud ( ep esen ed by blue con ou s) and dus ield (illus a ed wi h
colo ed con ou lines) om di e en model expe imen s (NoAERO-NoSIP, AERO-NoSIP,
and AERO-SIP) colloca ed o he ligh o 15-09-2022 a e depic ed. The igh column
depic s he High-Al i ude Lida Obse a o y (HALO) obse a ions om he NASA DC-8
En i on. Ea h Sci. P oc. 2025,35, 21 4 o 6
o cloud sc eened, ae osol olume backsca e coe icien a 532 nm, ela i e humidi y wi h
espec o ice (using MERRA-2 eanalysis empe a u e ields), and dus mixing a io o
he same ligh [
17
]. The dus laye dep h is well cap u ed wi hin he obse ed al i ude
ange (0–4.5 km). Be ween 5.5 and 8 km, egions wi h ela i e humidi y (RH) wi h espec
o ice g ea e han 100% a e obse ed, indica ing he p esence o cold clouds. In all
h ee model expe imen s, he cold cloud scene is ep oduced. Howe e , di e ences a ise
in he simula ed IWC ac oss he simula ions. In he AERO-NoSIP and AERO-SIP cases,
he cold cloud appea s less dense and mo e agmen ed han in he NoAERO-NoSIP
case. This can be a ibu ed o he ac ha empe a u e-awa e pa ame e iza ion ends
o o e es ima e ice c ys al concen a ions [
18
]. The cold clouds simula ed in he AERO-
NoSIP and AERO-SIP expe imen s consis o b oken cloud s uc u es, ea u ing h ee and
wo dis inc co es, espec i ely.
Figu e 4. The simula ed cold cloud ( ep esen ed by blue con ou s) and dus ield (illus a ed wi h
colo ed con ou lines) om di e en model expe imen s (NoAERO-NoSIP, AERO-NoSIP, AERO-SIP)
(le ) colloca ed o he CPEX-CV ligh o 15 Sep embe 2022. The HALO-obse ed ae osol backsca e ,
ela i e humidi y wi h espec o ice, and dus mixing a io o he ligh o 15 Sep embe 2022 ( igh ).
4. Fu u e S eps
Building on he ini ial mesoscale simula ions and he implemen a ion o he ae osol-
awa e ice nuclea ion scheme, he nex phase o his wo k will ocus on u he analysis and
e inemen . Speci ically, we plan o ca y ou he ollowing:
•
Pe o m de ailed compa isons o model ou pu s wi h a ailable g ound-based and
ai bo ne ada measu emen s o e alua e he accu acy o cloud and ice s uc u e
simula ions. This will help alida e he sensi i i y o he modeled IWP and LWP o
ae osol–cloud in e ac ions.
•
Conduc la ge-eddy simula ions (LESs) o selec ed days ha exhibi ed signi ican
di e ences be ween simula ion se ups in o de o mo e accu a ely esol e cloud
dynamics and mic ophysical p ocesses in luenced by mine al dus .
•
Inco po a e assimila ed ae osol ields in o he LES amewo k o be e cons ain he
ep esen a ion o dus laye s and imp o e model ini ializa ions.
•Ex end he simula ions using a ailable da a om mo e ecen campaigns.
These s eps will s eng hen he linkage be ween obse ed and modeled cloud s uc-
u es and con ibu e o an imp o ed unde s anding and ep esen a ion o dus -d i en ice
nuclea ion in egional and global clima e models.
En i on. Ea h Sci. P oc. 2025,35, 21 5 o 6
Au ho Con ibu ions: Concep ualiza ion, E.D., E.M., and V.A.; me hodology, E.D., E.M., V.A., P.K.;
so wa e, E.D.; da a, E.D. and A.R.N.; alida ion, E.D.; in es iga ion, E.D. and E.M.; esou ces, E.D.
and V.A.; w i ing—o iginal d a p epa a ion, E.D.; w i ing— e iew and edi ing, all. All au ho s
ha e ead and ag eed o he published e sion o he manusc ip .
Funding: This esea ch was unded by he Ho izon Eu ope p og am unde g an ag eemen no.
101137680 ia he p ojec CERTAINTY (Cloud-aERosol inTe ac ions & hei impAc s IN The ea h
sYs em) and by he PANGEA4CalVal p ojec (g an ag eemen 101079201) unded by he Eu opean
Union. This wo k is a con ibu ion o he AIRSENSE p ojec , which is pa o he A mosphe e Science
and he Ho izon Eu ope p og am CiROCCO p ojec (unde g an ag eemen no. 101086497). The
iews and opinions exp essed a e, howe e , hose o he au ho (s) only and do no necessa ily e lec
hose o he Eu opean Union o REA. Nei he he Eu opean Union no REA can be held esponsible
o hem.
Ins i u ional Re iew Boa d S a emen : No applicable.
In o med Consen S a emen : No applicable.
Da a A ailabili y S a emen : Da a a e a ailable upon eques o Eleni D akaki ([email p o ec ed])
and Eleni Ma inou ([email p o ec ed]). HALO ai bo ne da a a e openly a ailable a h ps://www-
ai .la c.nasa.go /cgi-bin/A cView/cpex.2022#NEHRIR.AMIN/ (accessed 8 Sep embe 2025).
Acknowledgmen s: This wo k was suppo ed by compu a ional ime g an ed by he Na ional
In as uc u es o Resea ch and Technology S.A. (GRNET S.A.) in he Na ional HPC acili y—ARIS—
unde p ojec ID p 016030_ hin_MIAMI. We would also like o hank he nume ous de elope s who
con ibu ed o he ee and open-sou ce ools used o he da a isualiza ion and analysis, pa icula ly
Ma plo lib [19], xa ay [20], and Ca opy [21].
Con lic s o In e es : The au ho s decla e no con lic o in e es .
Abb e ia ions
The ollowing abb e ia ions a e used in his manusc ip :
LWP Liquid wa e pa h
IWP Ice wa e pa h
HALO High-Al i ude Lida Obse a o y
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Disclaime /Publishe ’s No e: The s a emen s, opinions and da a con ained in all publica ions a e solely hose o he indi idual
au ho (s) and con ibu o (s) and no o MDPI and/o he edi o (s). MDPI and/o he edi o (s) disclaim esponsibili y o any inju y o
people o p ope y esul ing om any ideas, me hods, ins uc ions o p oduc s e e ed o in he con en .
