The 2023 Southern California Interactions of Low cloud and Land Aerosol (SCILLA) aircraft field expe
Abstract
Project AbstractWe propose the Southern California Interactions of Low Cloud and Land Aerosol (SCILLA) exper?iment. The over-arching, goal of this experiment is to understand the interplay among horizontalcirculation, vertical mixing, aerosols and clouds in the Sou,thern California (SoCal) Bight. Thehorizontal circulation in the Bight region underlies all of our scientific interests. Eddy circul,ationswitin the Bight are almost always present when low clouds are persistent, and the transport of pol?lution into the Bight also,depends on the regional and local circulation. The contrast between thecooler near-surface marine air with the warmer overlying cont,inental and/or free tropospheric airis crucial to the efficiency of vertical mixing, and vertical transport of aerosol into the boun,darylayer. We specifically propose to base the CIRPAS Twin Otter aircraft in San Diego, CA, to per?form airborne measurements of win,ds, aerosols, and clouds for 1 month (June to July 2023), witha geographical focus on the SoCal Bight. This deployment would coincid,e with the DOE-fundedEastern Pacific Cloud Aerosol Precipitation Experiment (EPCAPE), which will deploy a range ofground-based aeros,ol and cloud sensors and samplers from Feb. 2023 to Feb. 2024, mostly in andaround San Diego. SCILLA and EPCAPE will benefit from da,ta collected by each other.The aircraft deployment will specifically answer the following questions, with the associated apriori nul,l hypotheses:1: What causes regions of elevated cloud drop number concentration in the SoCal Bight? Nullhypothesis: Transport of rem,ote continental aerosol causes the regions of elevated cloud dropnumber concentration.2: Is the continental aerosol transport mainly, from horizontal advection, or does vertical transportand mixing play a key role? Null hypothesis: Because continental air tends to,be warmer thanmarine air, continental aerosol is initially transported offshore above the boundary layer, and thusa vertical transpo,rt mechanism is needed to produce elevated cloud drop number concentration.3: What is the role of the thermodynamic properties (rath,er than aerosol properties) of continentalair in modifying clouds in the SoCal Bight? Null hypothesis: Layers of warm and dry contin,entalair above the boundary layer will significantly impact cloud properties in the SoCal Bight viaturbulent mixing of energy and mo,isture.DoD Impact: Successful identification of aerosol provenance from in situ measurements will bea powerful tool for evaluating m,odel predictive ability. Field measurements from SCILLA willbe used to constrain the performance of current operational models run a,t Fleet Numerical Mete?orology and Oceanography Center (as well as the next-generation global prediction model NavyEnvironmental Pre,diction system Utilizing the NUMA corE or NEPTUNE), which is targeting3 km global horizontal grid spacing. In addition, we will perf,orm detailed characterization ofthe aerosol and cloud microphysical state of the marine atmosphere to inform parameterizationsof vis,ibility and electromagnetic/electro-optical (EM/EO) propagation through clouds that will berequired in predictive models for the for,eseeable future
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 07, 2022
- Source ID
- N000142212752
Entities
People
- Patrick Chuang
Organizations
- Office of Naval Research
- United States Navy
- University of California, Santa Cruz