Published May 31, 2024 | Version v1
Dataset Metadata-only

Datasets used in Kokkola et al. (2024) "Model analysis of biases in satellite diagnosed aerosol effect on cloud liquid water path"

Creators

  • 1. Atmospheric Research Centre of Eastern Finland, Finnish Meteorological Institute, Kuopio, Finland
  • 2. CSC - IT Center for Science, Espoo, Finland
  • 3. Datrix S.p.A., Milan, Italy

Description

This study aims to explore possible causes in the decreasing trend of liquid water path (LWP) with increasing cloud droplet number concentrations (CDNC) obtained by satellite-based studies. Datasets comprise cloud properties derived from UCLALES-SALSA simulations of a typical marine stratocumulus cloud setup (nocturnal drizzling stratocumulus cloud DYCOMS-II RF02 of the Second Dynamics and Chemistry of Marine Stratocumulus field campaign (Ackerman et al., 2009. Mon. Wea. Rev., 137, 1083–1110). Model-based properties were used to calculate LWP and CDNC with two different equations commonly used in satellite data analysis. Deviations between model and satellite-retrievals are included as relative percentage error.

Methods

Cloud top properties included in these datasets were obtained with a sampling methodology that mimics this so-called penetration depth bias (Grosvenor et al. 2018, AMT, 11(7), 4273–4289). Datasets include properties in a cloud upper region comprising as many model layers as needed to reduce by three units the cloud optical thickness in the infrared region (2.38 um -4.00 um to get a surrogate of MODIS retrievals at the 2.13 um um channels) below its maximum value. All properties are calculated as extinction coefficient weighted average values that consider all model layers in the selected cloud upper region. Cloud optical thickness was calculated for the visible wavelength band (0.25 um - 0.65 um) as a surrogate of MODIS retrievals at 0.66 um.

Technical info

Simulations were performed in a horizontal model domain size of 51 Km by 51 Km and a vertical domain extending up to 1.4 Km. Horizontal and vertical resolutions were set to be 75 m and 20 m, respectively. Equations were resolved with a maximum time step of 1 s using an hourly period for spinup without nudging. To determine the effect of aerosol on cloud properties, we ran a set of 3 simulations with initial accumulation model aerosol concentrations of 65, 150 and 300 #/cm3 (corresponding to the total number concentrations of 78, 180 and 360 #/cm3). In our datasets, we have included cloud properties sampled at 2 h, 6h and 10h from the start of the run. Each file was labeled using this information, for example the file CloudTop_prop_acc150_6h.nc contains snapshots of cloud top properties at 6.2 h, 6.3 h and 6.5 h for the simulation scenario initialized with an aerosol concentration of 150 #/cm3 in the accumulation mode.

Table of contents

Datasets have been divided in two containers according to the spatial resolution. Container 1 : 2003163_DYCOMS_II_RF02_cloud_prop_75 m_75m including 9 ncfiles, three sampling times and three simulation scenarios initialized with different aerosol loadings. Each file shows cloud property fields in the original horizontal resolution of simulations. Container 2 : 2003163_DYCOMS_II_RF02_cloud_prop_1425m_1425m including 9 ncfiles, three sampling times and three simulation scenarios initialized with different aerosol loadings. Original horizontal resolution in simulations. Each file shows cloud property fields spatially aggregated in subdomains of 1.425 Km by 1.425 Km (19 model vertical columns each one with 75 m by 75 m). Spatially-aggregated properties are obtained using cloud optical thickness in cloudy columns as a weighting factor during horizontal averaging operations along subdomains.

Additional details

Identifiers

URL
https://etsin.fairdata.fi/dataset/b576742d-073e-4641-878b-66d5b10ad9e8
b2rec
8fc77f2c6a8a4deab3de2efd46683010

Funding

European Union's Horizon 2020 research and innovation programme
FORCeS Constrained aerosol forcing for improved climate projections 82105
Research Council of Finland
Atmosphere and Climate Competence Centre, ACCC 337549
Research Council of Finland
BSOA-BoRE Are Biogenic Secondary Organic Aerosols Climatically Significant in the Boreal Region? 339885
European Union's Horizon 2020 research and innovation programme
CERTAINTY Cloud-aERosol inTeractions & their impActs IN The earth sYstem 101137680
Marie Sklodowska-Curie Actions (MSCA) of the European Union (EU)
COmputatioNal Imaging as a training Network for Smart biomedical dEvices 101072354

Instruments

Not applicable.
undefined (Other)

FMI metadata

Link to external data location (URL)
https://a3s.fi/2003163_DYCOMS_II_RF02_cloud_prop_75m_75m/index.html, https://a3s.fi/2003163_DYCOMS_II_RF02_cloud_prop_1425m_1425m/index.html
Process step
Raw data as time series of 3D cloud macroscopical properties and cloud microphysical properties in binned aerosol and hydrometeors distributions generated by UCLALES-SALSA., Processed data as time series of 2D cloud macro and microscopical properties corresponding to the extended cloud top section.
Lineage
Structured data processed by user-based classification.
Model
Large-eddy-simulations were performed with UCLALES-SALSA (DEV branch version November, 2023) available from https://github.com/UCLALES-SALSA/UCLALES-SALSA/tree/DEV
Parameter
  • Parameter name: LWP
  • Parameter unit: kg/m2
  • Parameter description: Liquid water path considering just cloudy layers where liquid water content LWC >0.01 gm-3
  • Parameter name: CDNC
  • Parameter unit: #/cm3
  • Parameter description: Cloud droplet number concentration as an extinction coefficient weighted value across cloud top layers (include droplets between 2 µm -80 µm)
  • Parameter name: CER_bext
  • Parameter unit: m
  • Parameter description: Cloud droplet effective radius as an extinction coefficient weighted value across the extended cloud top. Extinction coefficients calculated for 2.38um-4.00um band
  • Parameter name: COT
  • Parameter unit: Dimensionless
  • Parameter description: Cloud optical thickness in the wavelength range of 250-690 nm
  • Parameter name: CER
  • Parameter unit: m
  • Parameter description: Cloud droplet effective radius as count-mean value across cloud top layers
  • Parameter name: fadiab
  • Parameter unit: Dimensionless
  • Parameter description: Adiabatic fraction derived for LWP as in Brenguier et al., 2000. Journal of the Atmospheric Sciences, 57(6), 803–821
  • Parameter name: k
  • Parameter unit: Dimensionless
  • Parameter description: Droplet distribution breadth as the ratio between mean volume radius and cloud droplet effective radius as MVR3/CER3
  • Parameter name: omega
  • Parameter unit: Dimensionless
  • Parameter description: ingle scattering coefficient in the wavelength range of 250-690 nm (Savijarvi et al. 1997. Quarterly Journal of the Royal Meteorological Society, 123(540), 883–899)
  • Parameter name: g
  • Parameter unit: Dimensionless
  • Parameter description: Asymmetry parameter in the wavelength range of 250-690 nm (Savijarvi et al. 1997. Quarterly Journal of the Royal Meteorological Society, 123(540), 883–899)
  • Parameter name: albedo
  • Parameter unit: Dimensionless
  • Parameter description: Cloud albedo calculated with the two-stream approximation without solar zenith angle correction
  • Parameter name: Htop
  • Parameter unit: m
  • Parameter description: Geometrical thickness of the extended cloud top (layers needed to to reduce the optical depth (@2.1 um) to 3 units from its maximum value
  • Parameter name: Hcloud
  • Parameter unit: m
  • Parameter description: Cloud geometrical thickness considering just cloudy layers where LWC >0.01 gm-3
  • Parameter name: MVR
  • Parameter unit: m
  • Parameter description: Mean droplet volume radius calculated as extinction coefficient weighted value across the extended cloud top
  • Parameter name: sfcrrate
  • Parameter unit: W/m2
  • Parameter description: Precipitation rate at the surface
  • Parameter name: ctoprrate
  • Parameter unit: W/m2
  • Parameter description: Precipitation rate at the extended cloud top
  • Parameter name: Temp
  • Parameter unit: K
  • Parameter description: Temperature at the extended cloud top
  • Parameter name: Press
  • Parameter unit: Pa
  • Parameter description: Pressure at the extended cloud top
  • Parameter name: cwCT
  • Parameter unit: kg/m4
  • Parameter description: Water content lapse rate at the extended cloud top
  • Parameter name: CDNC_sat_Q
  • Parameter unit: #/cm3
  • Parameter description: Cloud droplet number concentration calculated using CER_bext and COT in equation in Quaas et al. 2020. ACP, 20(23), 15079–15099
  • Parameter name: CDNC_sat_Q_noise
  • Parameter unit: #cm3
  • Parameter description: Cloud droplet number concentration calculated using CER_bext and COT in equation in Quaas et al. 2020. ACP, 20(23), 15079–15099 but adding 20% noise in CER and COT values.
  • Parameter name: CDNC_sat_Q_dev
  • Parameter unit: %
  • Parameter description: Relative percentage error in CDNC between UCLALES-SALSA and equation in Quaas et al. 2020. ACP, 20(23), 15079–15099
  • Parameter name: LWP_sat_Q
  • Parameter unit: kg/m2
  • Parameter description: Liquid water path calculated using CER_bext and COT equation in Quaas et al. 2020. ACP, 20(23), 15079–15099
  • Parameter name: LWP_sat_Q_noise
  • Parameter unit: kg/m2
  • Parameter description: Liquid water path calculated using CER_bext and COT in equation in Quaas et al. 2020. ACP, 20(23), 15079–15099 but adding 20% noise in CER and COT values
  • Parameter name: LWP_sat_Q_dev
  • Parameter unit: %
  • Parameter description: Relative percentage error in LWP between UCLALES-SALSA and equation in Quaas et al. 2020. ACP, 20(23), 15079–15099
  • Parameter name: CDNC_sat_G
  • Parameter unit: #/cm3
  • Parameter description: Cloud droplet number concentration calculated using CER_bext, COT, k, fadiab and cwCT in equation in Grosvenor et al. 2018. Reviews of Geophysics, 56(2), 409–453
  • Parameter name: CDNC_sat_G_noise
  • Parameter unit: #/cm3
  • Parameter description: Cloud droplet number concentration calculated using using CER_bext, COT, k, fadiab and cwCT in equation in Grosvenor et al. 2018. Reviews of Geophysics, 56(2), 409–453 but adding 20% noise in CER and COT values
  • Parameter name: CDNC_sat_G_dev
  • Parameter unit: %
  • Parameter description: Relative percentage error in CDNC between UCLALES-SALSA and equation in Grosvenor et al. 2018. Reviews of Geophysics, 56(2), 409–453
Data levels (meter, hectoPascal, degree, sigma pressure levels, other) in vertical direction(+/-) for example 1500 m or 850 hPa
  • Level: 20 m
Resolution
75
Resolution unit
m
Topic category
climatologyMeteorologyAtmosphere

Temporal Coverage

Ranges:

Start date:
End date: 2001-07-11

Locations

Coast of Southern California in the United Sates of America, Northeast Pacific ocean Point:
(Lon: 31.4, Lat: -121.7 )