Examining the Relationship Between Precipitation and TOA Net Radiation

Kim Chamales

MPO 524 Final Project

Thursday, May 2nd, 2013

My Research

• Examining the effects of external forcing on precipitation in the tropical Atlantic

• Looking at the relationship between precipitation and TOA net radiation in two simulations with varying precessional forcing

• Examining changes in tropical Atlantic precipitation – so changes in monsoons and ITCZ

My Data

• GFDL-CM2.1 (fully coupled)• Two simulations representing both

extremes of precessional forcing• Climatological monthly averages from

20 years of the equilibrium climate• Over entire globe: 144x90x12

Precessional Forcing

1. Winter Solstice (WSOL): NH winter solstice closest to the sun

2. Summer Solstice (SSOL): NH summer solstice closest to the sun

JJA JJADJF DJF

Precipitation Difference: WSOL – SSOL

Earth is closer to the sun Earth is farther from the sun

Why use this analysis?• Can’t think of monsoons as land and sea

breezes being driven by surface temperature

change in TOA net radiation

surface energy storage

atmos energy flux div

ocean energy flux div

Land and atmospheric energy storage are very small so they are neglected.

Merlis et al. (2012b), Equations 5 & 6

200 300 0 100

Summary

• Examining spatial and temporal relationship between precipitation and TOA net radiation

• Although it gives some useful information about the relationship, the variability between the two in the tropics is very large

Thank You!

Extra Slides

The downfall of using climatological averages…

• Can’t do a lot of the analyses we learned in class because we don’t have a time series!

• However, the relationships that exist in the data should still exist – we have just averaged out a lot of the variability

• Can still use certain analyses to gather useful information