Earth System Prediction with the Subseasonal Experiment (SubX)

Kathy PegionGeorge Mason University, Dept of Atmospheric, Oceanic, and Earth Sciences

Center for Ocean-Land-Atmosphere Studies

Valid Jun 28 – Jul 12

The Subseasonal Experiment (SubX)

From White, C, …. K. Pegion, … 2017, J. Royal. Met. Soc.

Forecasts available in real-time

Research models included

SubX BY THE NUMBERS

7 Global Models

17 Years of weekly

Retrospective Forecasts

~2 Years of weekly

Real-time Forecasts

3-4 week guidance

for Climate Prediction Center Outlooks

CESM-30LCESM1 A,O,I,L 10 45 1999-2016 SEAS/Dec/CC R

CESM-46LCESM1 A,O,I,L 10 45 1999-2016 SEAS/Dec/CC R

The Subseasonal Experiment (SubX)

Pegion et al. 2019, BAMS revised

SubX Multi-model Biases Week-1

2m Temperature Precipitation

Anomaly Correlation 2m Temperature Week 3

Pegion et al. 2019, BAMS revised

SubX Average Anomaly Correlation North America Week 3-4

Overall subseasonal skill is low

But, subseasonal skill varies:RegionSeasonTime

Skill of Week 3 Jan Re-forecasts

Pegion et al. 2019, BAMS revised

For this timescale, focus on forecasts opportunity

• Models fail to predict the MJO convection, associated circulations, and moisture advection processes beyond 10 days

• Models have mean biases across the Indo-Pacific: a drier low troposphere, excess of surface precipitation, frequent occurrence of light precipitation.

Kim, Janiga, Pegion, submitted to JGR

Understanding ProcessesEvaluating Skill

Madden-Julian Oscillation (MJO)

Pegion et al. 2019, BAMS revised

Where to find more information: http://cola.gmu.edu/kpegion/subx/ • SubX BAMS

Paper (revised)

• SubX MJO Paper, (submitted)

• SubX Data Users Guide

• Codes for Downloading and processing data

• Model Evaluation Plots

• Real-time Forecast Plots