The radiative budget of an atmospheric column in tropical western pacific
Download
1 / 22

The Radiative Budget of an Atmospheric Column in Tropical Western Pacific - PowerPoint PPT Presentation


  • 214 Views
  • Uploaded on

The Radiative Budget of an Atmospheric Column in Tropical Western Pacific. Zheng Liu 1 Thomas Ackerman 1,2 , Sally McFarlane 2 , Jim Mather 2 , 1 University of Washington 2 Pacific Northwest National Laboratory. Background. Motivation: Cloud and water vapor feed back → model sensitivity

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'The Radiative Budget of an Atmospheric Column in Tropical Western Pacific' - ivanbritt


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
The radiative budget of an atmospheric column in tropical western pacific l.jpg

The Radiative Budget of an Atmospheric Column in Tropical Western Pacific

Zheng Liu1Thomas Ackerman1,2, Sally McFarlane2, Jim Mather2,

1University of Washington

2 Pacific Northwest National Laboratory


Background l.jpg
Background Western Pacific

  • Motivation:

    • Cloud and water vapor feed back → model sensitivity

    • Cloud and radiative parameterization → feed back

      ↓↓

  • Model evaluation:

    • Need : Radiative budgets at TOA, surface

      Column absorption,

    • Limited measurements → start with some atmospheric columns:Manus and Nauru


Data set description observational dataset l.jpg
Data Set Description: Observational Dataset Western Pacific

  • TOA net SW and LW fluxes:

    • GMS hourly observations, 0.3o x 0.3o grid (about 30km x 30 km)

  • Surface SW&LW downward fluxes:

    • ARM surface measurements, daily averaged from 1-min data

  • Surface LW upward fluxes:

    • NOAA optimum interpolated SST, weekly averaged, 1o x 1o grid

  • Surface SW upward fluxes:

    • Assumed sea surface SW albedo (6%)


Data set description radiative model calculations l.jpg
Data Set Description: Western PacificRadiative Model Calculations

  • Computed fluxes and heating rates from ARM column observations

    • Retrieve vertical profiles of cloud microphysical properties from ARM millimeter wave radar data

    • Temperature and water vapor profiles from radiosonde launches

    • Sample the cloud properties every 5 minutes and perform radiative transfer only on the sampled profiles.

    • Calculate broadband fluxes


Data set description climate model l.jpg
Data Set Description: Climate Model Western Pacific

  • NCAR Community Atmosphere Model (CAM)

    • T42 resolution

    • Prescribed SST

    • Compare values from box over Manus (280 km x 280 km) with observations

  • Multi-scale modeling framework (MMF)

    • Embedded 2D cloud system resolving model (64 columns each 4 km in horizontal dimension)

    • Prescribed SST

    • Average 64 column values within Manus gridbox


Observation v s radiative model l.jpg
Observation v.s. Radiative Model Western Pacific

  • Frequency distribution → day to day comparison

  • TOA → Surface → Column absorption

  • Page organization:


Remarks l.jpg
Remarks Western Pacific

  • SW clearsky offset

  • SW allsky “cumulus” effects

  • Manus is convectively more active than Nauru.


Observation v s models l.jpg
Observation v.s. Models Western Pacific

  • Observation: Jun 16, 1999 ~ May 21, 2003

  • Climate models: Jan 1, 1999 ~ Dec 31, 1999

  • Radiative model calculation:

    • Manus: Feb 25, 2000 ~ Jul 31, 2000

    • Nauru: Mar 9, 1999 ~ Dec 19, 1999


Conclusion l.jpg
Conclusion Western Pacific

  • Evaluation of the radiative budget of atmospheric columns can help understand the convective tropics

  • Discrepancy between calculations from radiative model and observations is probably due to scene mismatch between TOA and the surface and some 3D effects

  • Column SW absorption:

    • Clear sky: around 90w/m2

    • All sky:

      • almost unaffected by cloud for both radative model and climate models

      • much greater variation according to observational data and bias towards more absorption than clear sky


Future work l.jpg
Future work Western Pacific

  • Compare with other TOA satellite data sets: ISCCP, CERES

  • Compare budget results from CAM run in forecast mode with observational data and climate model version of CAM

  • Compare surface radiative budget from satellite with ARM surface measurement


Acknowledgements l.jpg
Acknowledgements Western Pacific

  • Professor Ackerman

  • Sally Mcfarlane, Professor Fu, Professor Wood

  • All my first year classmates

  • All the audience here


ad