Introduction
The western Pacific warm pool is the region, which has highest sea surface temperatures (SSSTs), hence is recognized as a heat reservoir for global atmospheric circulation. Although interannual variability of the SST on that region is closely related to ENSO variability, meridional shifts of the northern SST front in the seasonal timescale are also significant. In addition, diurnal, decadal, and multi-decadal signals also appear on that region. This multi-timescale variability affects various processes on momentum, heat, and fresh water balance of the western Pacific warm pool. Behavior of Western Pacific warm pool is a Key factor not only for surrounding countries but also for world weather and climate. However, detailed explanation of the associated processes and evaluation of teleconnection effect are still unclear.
To understand ocean oriented climate phenomenon,which have multi-timescale variability, we conduct in situ observations on the northern edge of the Western Pacific warm pool by multiplatform; Research vessels, moorings, floats, drifters, unmanned surface vehicles, for oceanic and atmoshperic variables. Utilizing the combination of the long term moorings and process study by other platforms, we try to capture detailed processes on the SST frontal zone on that region, and analyze underlying mechanisms.
Observations
- Philippine Sea mooring (PHSMO)
A surface mooring, which named Philippine Sea mooring (PHSMO), has been deployed at nominal location of 13˚N 137˚E from December 2016 for monitoring climate variability in the northern edge of Pacific warm pool region. The mooring also works as a reference station for air-sea interaction. The mooring has meteorological sensors for winds, air temperature, relative humidity, barometric pressure, downward shortwave and longwave radiations, and rainfall. The mooring also contains oceanic sensors for upper ocean temperature, salinity and currents. For biogeochemical measurements, several dissolved oxygen sensors were installed around mean thermocline depth of 100 m. The observed data are used for Northern edge of warm pool study, which includes understanding of climate variability and its associated processes of air-sea interaction.
- Flux Glider
We use the Wave Glider made by Liquid Robotics, Inc. as a platform for air-sea heat and momentum flux measurements. The payload units for air-sea heat and momentum flux measurements were developed by JAMSTEC, based on the technology of long-term TRITON moorings. The observed variables are winds, sea surface temperature, air temperature, relative humidity, shortwave radiation, longwave radiation, and surface currents. From those measurements, we can derive turbulent and radiative fluxes.
- Process study for air-sea interaction by R/V Mirai
For the purpose of deeply understanding for air-sea interaction on northern part of the western Pacific warm pool and its effects on the climate variability, we conduct several cruises in every 1-2 years. Our targets are the atmospheric valiability with cumulus convection, which has spatial scales from synoptic to meso scales, the ocean mixed layer variability, which has time scales from intraseasonal to decadal scales, and the mechanism of formation processes for SST fronts and spatial structure of the mixed layer. The shipboard observations include Doppler radar, lider, radio sonde, surface meteorological measurements, CTD, ADCP, and so on.
Data
The data of Northern Edge of Warm pool Study can be accessed via below links.
