Group 4 - Aerosol optical properties and Arctic Haze¶
- Dina, Bjørn, Sigrid, Eemeli, Dominik
- Maria, Olga
Aerosol chemical composition¶
Goals¶
- Change in chemical composition
- Compare models to observations
Data¶
- Observational data from EBAS (For now: sea salt, SO$_4$, trying to get: NH$_4$, NO$_3$, organic aerosol and black carbon).
- Model data: from the CMIP6 r1i1p1f1 run (For now: NorESM2-LM, Later: CESM2, CESM2_WACCAM, BCC-ESM1, GFDL-CM4 and GFDL_ESM4)
Difficulties¶
- Finding all the observational data
- Is the pyaerocom concss sea salt?
- What is the pyaerocom concso4?
Relative Humidity (RH): Models vs Observations¶
-Sigrid J. Bakke
Motivation¶
- We are interested in Optical properties
- Optical properties (models vs measurements) are compared for same RH.
- So if the RH is wrong in one of them, we are comparing the wrong optical properties
- Thus, important to know how well RH is modelled
Goal¶
- Compare modelled RH to observed RH
- How well models represent observations
- (to see if the model perform differently depending on region, seasonality, statistic etc.)
Data¶
- Model data: CMIP6 (CESM2, CanESM5, IPSL-CM6A-LR) and ATRAS
- Obs data: stations at Svalbard, hopefully expand to other locations
Optical properties: Dry scattering and hygroscopicity¶
- Search for inconsistencies in the models according to scattering of dry cases
- How does the different models capture scattering?
- How do models represent the hygroscopic growth between 0 and 40 RH?
- Do these by comparing the data between the models and measurements?
Data used:¶
- Models: CAM5-Atras, CAM5, GEOS-Chem, ECMWF, GEOS5-Globase, MERRAero, OSLO-CTM3, CAM5-Oslo, TM5-AP3
- Measurements: EBAS scattering coefficients 550nm
Challenges:¶
- Pyaerocom does not have the data available
- consistencies in the model outputs
Aerosol optical hygroscopic growth¶
-Dominic Heslin-Rees
- Hygroscopic growth
- Light scattering enhancement factor [$f(RH, \lambda)$]
Research Questions¶
- Discrepancies between model and Obserbvations
- Differences between surface and vertical column (at pressure level) in model output
- Reasons for discrepancies
Data¶
- Model data (CAM, Atras, Chem, ECMWF, Globase, Oslo CTM3 \& TM5)
- In situ groud based measurements from Zeppelin, Barrow \& (Hyytiälä)
Preliminary results¶
- Models overestimate [$f(RH, \lambda)$] (e.g. for Atras at Barrow):
Problems¶
- The datasets are not matching (e.g. Zeppelin has 3 months in 2008 \& model = 2010)