On the Choco Low-level Jet and gravity waves over the rainiest place on Earth: Observations and Simulations during CHOCO-JEX
Abstract
The far eastern Pacific and western Colombia houses the rainiest place on Earth. The existence of such world-record breaking precipitation spot has been explained in terms of ocean-atmosphere-land (western Andes) interactions enhanced by the dynamics of the Choco low-level jet (ChocoLLJ). An international initiative to investigate the troposphere dynamical and thermodynamical characteristics of the troposphere over the region was developed during 2016, including four Intensive Observing Periods (IOP) as part of the CHOCO-JEX research program. The IOPs consisted in 8-days intensive observations using upper-air soundings over the Colombian Pacific maritime and inland regions. CHOCO-JEX allowed us to identify, for the first time, the existence of the ChocoLLJ, mainly observed during the last oceanic campaign (November, 2016) through zonal winds of 4-5 m/s. However, atmospheric conditions were affected by La Niña and hurricane Otto passing from Caribbean Sea to Pacific Ocean. The last campaign also motivated us to perform a set of sensitivity experiments using WRF to test the gravity wave hypothesis (Mapes et al., MWR, 2003b) as precursor of morning offshore rainfall. Although all three sensitivity experiments at 36 (d01), 12 (d02) and 4 (d03) km were able to capture the general regional features, only d03 shows the morning peak over the coast. Observed and simulated thermodynamic profiles reveal diurnally varying temperature perturbations in coherence with the propagation of the gravity waves from mid to upper levels of the western Andes.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.A43H3112Y
- Keywords:
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- 3314 Convective processes;
- ATMOSPHERIC PROCESSES