CLIVAR Research Foci !  Variability and predictability of monsoons !  Decadal variability and predictability !  Marine biophysical interactions and upwellings !  Sea Level Rise and Regional Impacts !  Trends, nonlinearities and extreme events !  ENSO in a changing climate !  Heat balance and ocean heat storage

Air-Sea Fluxes Sergey Gulev and Carol Anne Clayson

Surface fluxes across CLIVAR research foci

Monsoons: 100-200 W/m2 change of Qnet during few weeks of the MBC

Sabin and Joseph 2008

Ping Chang: surface flux – SST relationship is scale dependent on mesoscales and synoptic scales

!

Air-sea flux

SST

Surface fluxes and predictability – synoptic scales (space-time resolution matters)

¼ OAFLUX (1987- onwards) – LIsan Yu

Extreme surface fluxes forcing the storm tracks and atmospheric moisture transport

Extremes:

extreme fluxes may amount to 2000+ W/m2 " extreme diabatic signals " storm tracks " energy and moisture transportswind-wave interations " generating extreme seas

Tilinina and Gulev 2014 Dufour and Zolina 2014

Surface fluxes and predictability – interannual and multidecadal scales

Gulev et al. 2013

Short-term residue

Long-term component

Sea level rise – directly connected with OHC change: #  Qe = 1 W/m2 annually = 12 mm MSL #  Surface heat flux " OHC change " MSL change

From Karina von Schuckmann

AR5, IPCC 2013

Requirements for surface flux accuracy – process and space-time scale dependence

(no single requirement)

Most of the available flux data sets suffer from systematic biases and fail to satisfy energy constraints: heat budget closure remains a significant problem. Discussed in Josey et al. (2013).

Courtesy: Josey, 2014, in prep.)

Josey, S. A., S. Gulev and L. Yu, 2013: Exchanges through the ocean surface, in Siedler, G., Griffies, S., Gould, J. and Church, J. (Eds.): Ocean Circulation and Climate 2nd Ed. A 21st century perspective, Academic Press, International Geophysics Series, Volume 103, p. 115-140.

The Global Ocean Heat Budget Closure Problem

SEAFLUX

Surface flux - related science questions

Global and regional ocean heat balances – consistency with OHC changes

Regional ocean heat budgets (whether the closure is possible at all, if yes – where? (CAGES)

Synoptic variability of the coupled system " moisture sources and predictability of stormtracks " predictability of ocean WBC

Interannual and decadal variability in the coupled system " decadal predictions and climate projections

Ocean precipitation, consistency of E-P with salinity changes

Reliability of air-sea fluxes in climate model simulations and the role of air-sea fluxes in climate feedbacks

Fluxes on very high resolution for forcing ocean GCMS

SH+LH, WHOI OA

SH+LH, NCEP-2

Yu and Weller 2007

Validating flux products against buoys

Yu et al. 2007

Lisan Yu 2014

200 400 600 800 1000 1200 1400

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Year Day

Heat

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Simon Josey: IMOS Southern Ocean Flux Station (SOFS) mooring, 47S/142 E, deployed Mar 2010. First year of data analysed (Schulz, Josey, Verein., 2012, GRL)

Ocean precipitation from satellites and reanalyses ! ocean fresh water budgets and salinity changes

TRMM GPCP

Sommer et al. 2014

Broken clouds Nearly clear sky conditions

We know practically nothing about the fluxes at very high resolution ! forcing for ocean GCMs is inconsistent with model resolution

CLIIPER 1/15º Jerome Chanut

Joint challenges of CLIVAR and GEWEX in fluxes

Inventory, classification and discrimination of the existing products by their accuracy and relevance for different purposes Satellite products, NWP (atmospheric reanalyses and operational analyses), VOS and in-situ, ocean reanalyses, blended products

Accuracy of state variables – from in-situ, satellites (retrievals), NWP

Space-time scaling of fluxes " understanding the applicability of parameterizations " Uncertainties associated with scaling

Ocean precipitation (validating GPCP, TRMM, potentially GPM, NWP and reanalyses; VOS-approach – does it have the future?) " in-situ campaigns

More observed fluxes (OCEANSites, more in mid and high latitudes

Test beds " forcing functions for OGCMs, synoptic air-sea interactions in mid latitudes (diabatic sources of heat and moisture), decadal and longer variability

GDAP

•  GDAP goal: describe complete Water and Energy budgets using consistent, long term, global datasets of radiative fluxes and surface energy exchanges as well as atmospheric parameters affecting energy balance

•  The products currently being coordinated: •  Clouds (ISCCP) •  Precipitation (GPCP) •  Aerosols (GACP) •  Ocean sensible and latent heat flux (SeaFlux) •  Land sensible and latent Heat flux (LandFlux) •  Surface as well as TOA radiative fluxes (SRB)

•  Also coordinating assessment of temperature/water vapor products to support above products (GVAP)

GEWEX Reference Products (pre-Integration)

+

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Validation

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Ships/Buoys

GEWEX Integrated Products

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SeaFlux overview

•  Project under GDAP to improve our understanding and determination of ocean surface turbulent fluxes

•  Our main questions: –  What is feasible in terms of resolution and length-of-time series for satellite data?

–  Can we produce a high resolution dataset using satellites that is better than conventional climatology and NWP products?

–  What are the best methods for creating this dataset? –  How do the different datasets perform under varying applications?

•  Elements of the SeaFlux project include: –  Evaluation/improvement of bulk turbulent flux models –  Evaluation of global flux products –  Providing library of flux datasets and in situ data sets for easy comparisons by researchers

–  Production of high-resolution (0.25o, 3 hourly) turbulent flux dataset

•  Near-surface air temperature and humidity (SSM/I only) –  Roberts et al. (2010) neural net technique –  Gap-filling methodology -- use of MERRA variability – 3 hour

•  Winds –  Uses CCMP winds (cross-calibrated SSM/I,

AMSR-E, TMI, QuikSCAT, SeaWinds) –  Gap-filling methodology -- use of MERRA variability – 3 hour

•  SST –  Pre-dawn based on Reynolds OISST –  Diurnal curve from new parameterization –  Needs peak solar radiation, precipitation

•  Uses neural net version of COARE •  Available at http://seaflux.org •  0.25 x 0.25 degree products, 3 hourly •  Uncertainty fields provided with data

1999 Latent Heat Flux

1999 Sensible Heat Flux

SeaFlux Climatological Data Set Version 1.0

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Latent Heat Flux

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Sensible Heat Flux

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Some sample comparisons

Regional Water Budgets

Conclusions from joint US CLIVAR/SeaFlux workshop on High Latitudes (2012)

•  Acquire more in situ observations (both limited duration focused on physical processes and long time series at given locations) –  Bulk parameters –  Direct flux observations (important also for improving bulk

flux parameterizations) •  Improved satellite flux datasets needed (coincident

measurements helpful) •  Increase accessibility of available datasets •  More flux intercomparisons with standardized methods

(Gille et al., Bourassa et al. papers describing workshop and outcomes)

MLD and surface flux effects on SST tendencies

Roberts and Clayson, 2014

Using multiple satellite and blended products

Color: SST spread Contours: mixed layer depth

Need to define what accuracy is for

The net heat flux error which would provide a seasonal SST spread less than one-half the peak to trough seasonal SST variability (Clayson and Bogdanoff 2013).

MJO variability and surface fluxes

Tromeur and Rossow, 2010

Weak MJO case Strong MJO case

- - - Weak MJO case

Ocean E-P comparisons

Robertson et al, 2014

Current combined activities

•  Continued discussions on comparisons/analysis of products

•  Developing focus group on consistency between planetary heat balance and ocean heat storage – Jointly led by CLIVAR (Karina von

Schuckmann) and GEWEX (Carol Anne Clayson)

– Met this week for breakout, attendance by CLIVAR and GDAP folks