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Explore the importance and impact of the South East Pacific (SEP) region on global climate with the VOCALS-UK project focusing on model biases, sensitivity to large-scale processes, and resolving oceanic heat budget.
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VOCALS-UK John Constable ‘Cloud Study’ 1822 Len Shaffrey and Thomas Toniazzo Walker Institute, University of Reading
The South East Pacific • The South East Pacific (SEP) region is a tightly coupled system involving poorly understood interactions between the ocean, the atmosphere, and the land. • The SEP region and other upwelling regions are poorly represented in coupled climate models. • Why is the SEP so important? It has a huge impact on the climate of the Pacific basin and its variability.
HadCM3 Experiments: The Importance of the SEP Interannual standard deviation of SSTs in HadCM3 control run. Standard deviation of SSTs in a run where the SST anomalies in the SEP region are relaxed to the monthly SST climatology of the coupled model.
HadCM3 Experiments: The Role of the Andes HadCM3 Control HadCM3 Displaced Andes HadCM3 SST errors against HadISST. 10m wind errors against ERA-40. SEP surface wind errors in HadCM3 appear to determined by the orography. A need for higher resolution?
VOCALS • VOCALS (VAMOS Ocean-Cloud-Atmosphere-Land Study) is an international project to understand the climate of the SEP. • VOCALS-REX is an international field experiment designed to better understand physical and chemical processes central to the climate system of the SEP region.
VOCALS • The aim of VOCALS-MOD is to understand the processes that determine the climate of the SEP in coupled ocean-atmosphere models and how the representation of those processes can be improved. • Understanding how resolution can improve the upwelling regions is one of the central objectives of VOCALS-MOD. The VOCALS-MOD modelling strategy. A high resolution ocean-atmosphere regional coupled model. The regional model is then upscaled to the global model.
VOCALS • A consortium bid was submitted to NERC for a UK contribution to the VOCALS field experiment and modelling project. • The ambition of VOCALS-UK is to reduce uncertainties in current and future climate projections, especially those associated with marine stratocumulus and coupled ocean atmosphere processes. • Using a high resolution global coupled climate model (HiGEM) to study the SEP region would dovetail nicely with the main VOCALS modelling effort.
HiGEM1.2 minus HadGEM1.2 annual mean 1.5m temperature difference (colours), 10m wind differences (vectors).
HiGEM1.2 minus HadGEM1.2 annual mean 1.5m temperature difference (colours), 10m wind differences (vectors) and total cloud differences (contour interval=0.1).
VOCALS-UK • If the submission is successful we are planning to: • Assess systematic model biases in the SEP and in the wider tropical Pacific and the effect of increased resolution in the atmosphere and in the ocean components, particularly in the simulation of the oceanic heat budget. • Explore the sensitivity of the SEP region to large-scale processes (orographic forcing, air-sea interaction, and cloud radiative feedbacks) using HiGEM and HadGEM • Use NWP techniques with NuGAM to analyse the growth of model errors compared to reanalysis and observational campaign data, especially those related with the interaction between the MBL and the cloud cover.
VOCALS-UK • If the submission is successful we are planning to: • Assess systematic model biases in the SEP and in the wider tropical Pacific and the effect of increased resolution in the atmosphere and in the ocean components, particularly in the simulation of the oceanic heat budget. • Explore the sensitivity of the SEP region to large-scale processes (orographic forcing, air-sea interaction, and cloud radiative feedbacks) using HiGEM and HadGEM • Use NWP techniques with NuGAM to analyse the growth of model errors compared to reanalysis and observational campaign data, especially those related with the interaction between the MBL and the cloud cover.
Ocean Heat Budget in the SEP Mesoscale eddy variability (Right: snapshot from ROMS) is important for oceanic heat budget of the SEP (Below: October eddy and mean temperature advection at 13oS in HiGEM) Eddy temperature advection (interval 10-8K day-1) Mean temperature advection (interval 10-8K day-1) Latitude Latitude