Global Oceanic Precipitation Global Oceanic Precipitation Variations in 2006Variations in 2006

Pingping Xie, John E. JanowiakPingping Xie, John E. JanowiakRobert Joyce, and Phillip A. ArkinRobert Joyce, and Phillip A. Arkin**

Climate Prediction CenterClimate Prediction CenterNOAA/NWS/NCEPNOAA/NWS/NCEP

* ESSIC / UMD* ESSIC / UMD

Objectives:Objectives:

Description of global oceanic precipitation variations in 2006

Examination of global oceanic precipitation and evaporation distributions in existing observations and their uncertainties

Monitoring Tools in CPCMonitoring Tools in CPC CMAP

CPC Merged Analysis of Precipitation (Xie and Arkin 1997) Precipitation defined by merging gauge observations with satellite

estimates from multiple sources Monthly / pentad analyses from 1979

CAMS-OPI Streamlined real-time version of monthly CMAP Over ocean, precipitation estimates derived from OLR Over land, analysis defined by combining gauge with satellite

observation

CMORPH CPC Morphing technique Combined use of satellite microwave and infrared (IR) observations High-resolution (8km / 30min) precipitation analysis over the globe Available real-time from December 2002

Precipitation Variations in 2006Precipitation Variations in 2006 Derived from CAMS-OPI

estimates

Annual mean of 2.812 mm/ day (1026.4Kg/m2)

Heavier than normal rainfall east of the maritime Continent

Large negative anomaly over eastern Indian ocean

Deficit precipitation over north Atlantic

Evolution of ENSOEvolution of ENSO Derived from CAMS-OPI

estimates

Weak El Nino conditions developed during mid-2006 and lasted through the rest of the year

Weak precipitation anomaly restricted over western Pacific

MJO ActivitiesMJO Activities Derived from

GPCP pentad analysis (Xie et al. 2003)

Weak MJO activities during 2006

Some MJO events of medium intensity during the end of 2006

Hurricane ActivitiesHurricane Activities Over the Atlantic ocean diminished in 2006 (9/5)

Over east Pacific one of the strongest in recent years (19/11)

Hurricane John (2006)Hurricane John (2006)

Examining Oceanic Fresh Water Flux Examining Oceanic Fresh Water Flux Objectives :

To document the mean climatology of global oceanic precipitation, evaporation and fresh water flux over global oceans using existing observation data sets;

To get insight into the uncertainties in the definition of the mean climatology of fresh water budget using these data sets

Precipitation Data Sets CMAP GPCP Version 2 TRMM 3B31 (PR/TMI combined)

Evaporation data Sets GSSTF Version 2 J-OFURO HOAPS Version 3 NOC Version 1.1a

Distribution of Annual ClimatologyDistribution of Annual ClimatologyPrecipitationPrecipitation

Similar patterns of spatial distribution

Differences in magnitude over ocean

Largest differences over ocean around Maritime Continent

Uncertainties in Annual ClimatologyUncertainties in Annual ClimatologyPrecipitationPrecipitation

Largest uncertainties (standard deviation among observations) over ITCZ and high latitudes

Standard Deviation about 10% of the mean values

Distribution of Annual ClimatologyDistribution of Annual ClimatologyEvaporationEvaporation

Similar patterns of spatial distribution, especially the three satellite-based data sets

Differences in magnitude over ocean

Largest differences over oceanic dry zones

Uncertainties in Annual ClimatologyUncertainties in Annual ClimatologyEvaporationEvaporation

Largest uncertainties over oceanic dry zones south / north of ITCZ and over oceans around the Maritime Continent

Standard Deviation about 10% of the mean values

Uncertainties in Annual ClimatologyUncertainties in Annual ClimatologyE - PE - P

Large uncertainties over most of the tropical oceans

Standard Deviation about 10% - 20% of the mean values

Less uncertainties in zonal mean

Sources of the UncertaintiesSources of the Uncertainties Lack of in-situ

observations over oceans

Imperfect satellite-based estimates (precipitation, wind, ..)

Differences in objective techniques to create the analyses

Summary:

Precipitation variations in 2006 are characterized by evolution of a weak El Nino, and negative precipitation anomalies over east Indian ocean

Climatology of global oceanic fresh water fluxhas been examined using observation from multiple sources. Uncertainties in defining the climatology has been explored;

Work is underway to trace down the sources of the uncertainties and to refine the

oceanic precipitation analyses