Climatology of ShCubulk entrainment at the SGP observatory€¦ · Climatology of ShCubulk...
Transcript of Climatology of ShCubulk entrainment at the SGP observatory€¦ · Climatology of ShCubulk...
Climatology of ShCu bulk entrainment at the SGP observatory
Daniel Kirshbaum, McGill UniversityKatia Lamer, Brookhaven National Lab
ARM/ASR 2020 PI meeting
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Shallow cumuli at the ARM SGP observatory
Method 1: Jensen and Del Genio (2006)
• 2021 individual ShCu cloudsØ Surface-based, cloud tops
< 5 km, depths > 250 mØ Computes fractional
entrainment rate (𝟄) required for parcel LNB to match cloud-top height
• Notable sensitivites: CAPE (+), RH (+), shear (+), cloud-base mass flux (-)ØNo sensitivity to cloud
width (not shown)
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Method 2: Drueke et al (2019; TKE)
• 128 1-h ShCu periodsØ Surface-based, cloud tops
< 5 km, depths > 250 mØ Use scaling of equilibrium
TKE budget to estimate 𝟄
• Strong dependence on RH (+), mb (-) and cloud-layer depth (-)
✏ ⇠ CAPE1/3
m2/3b zcld
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Preliminary conclusions and future work
• Two simple bulk entrainment retrievals give different perspectives on ShCuentrainmentØ Individual clouds vs cloud ensembles
• Robust positive sensitivity to environmental CAPE and RH, negative sensitivity to zcld and mbØAlso, positive sensitivity to vertical wind shear in JDG parcel method
• Future work:ØOther environmental sensitivities?ØDimensional analysis: nondimensional controlling parametersØ ERICA retrieval (Wagner et al 2013)Ø Repeat climatology at ENA site
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