Articles | Volume 8, issue 7
https://doi.org/10.5194/gmd-8-1943-2015
https://doi.org/10.5194/gmd-8-1943-2015
Development and technical paper
 | 
02 Jul 2015
Development and technical paper |  | 02 Jul 2015

Pan-spectral observing system simulation experiments of shortwave reflectance and long-wave radiance for climate model evaluation

D. R. Feldman, W. D. Collins, and J. L. Paige

Abstract. Top-of-atmosphere (TOA) spectrally resolved shortwave reflectances and long-wave radiances describe the response of the Earth's surface and atmosphere to feedback processes and human-induced forcings. In order to evaluate proposed long-duration spectral measurements, we have projected 21st Century changes from the Community Climate System Model (CCSM3.0) conducted for the Intergovernmental Panel on Climate Change (IPCC) A2 Emissions Scenario onto shortwave reflectance spectra from 300 to 2500 nm and long-wave radiance spectra from 2000 to 200 cm−1 at 8 nm and 1 cm−1 resolution, respectively. The radiative transfer calculations have been rigorously validated against published standards and produce complementary signals describing the climate system forcings and feedbacks. Additional demonstration experiments were performed with the Model for Interdisciplinary Research on Climate (MIROC5) and Hadley Centre Global Environment Model version 2 Earth System (HadGEM2-ES) models for the Representative Concentration Pathway 8.5 (RCP8.5) scenario. The calculations contain readily distinguishable signatures of low clouds, snow/ice, aerosols, temperature gradients, and water vapour distributions. The goal of this effort is to understand both how climate change alters reflected solar and emitted infrared spectra of the Earth and determine whether spectral measurements enhance our detection and attribution of climate change. This effort also presents a path forward to understand the characteristics of hyperspectral observational records needed to confront models and inline instrument simulation. Such simulation will enable a diverse set of comparisons between model results from coupled model intercomparisons and existing and proposed satellite instrument measurement systems.

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Short summary
This work describes a new type of observational simulator for directly comparing measurements and models that takes advantage of all of the information in spectrally resolved top-of-atmosphere data. It describes how to model how the spectrum of the Earth, both in the shortwave and the long wave, changes in response to climate forcings, and provides a path towards inline observational simulation for the upcoming Coupled Model Intercomparison Project – Phase 6.