NOAA High-resolution Blended Analysis of Daily SST and Ice. Data is from Sep 1981 and is on a 1/4 deg global grid.

The principal component (PC)-based indices of the North Atlantic Oscillation (NAO) are the time series of the leading Empirical Orthogonal Function (EOF) of SLP anomalies over the Atlantic sector, 20°-80°N, 90°W-40°E. These indices are used to measure the NAO throughout the year, tracking the seasonal movements of the Icelandic low and Azores high. These movements are illustrated in the Figures on this page. Positive values of the NAO index are typically associated with stronger-than-average westerlies over the middle latitudes, more intense weather systems over the North Atlantic and wetter/milder weather over western Europe.

The Atlantic Multi-decadal Oscillation (AMO) has been identified as a coherent mode of natural variability occurring in the North Atlantic Ocean with an estimated period of 60-80 years. It is based upon the average anomalies of sea surface temperatures (SST) in the North Atlantic basin, typically over 0-80N. To remove the climate change signal from the AMO index, users typically detrend the SST data at each gridpoint or detrend the spatially averaged time series. Trenberth and Shea (2006) recommend that the detrending be done by subtracting the global-mean SST anomaly time series from the spatially averaged time series. See the Expert Guidance by Dr. Kevin Trenberth for the rationale for the global-mean detrending approach. The Expert Guidance by Dr. Rong Zhang discusses the impacts and mechanisms of the AMO.

GOSUD aims at assembling in-situ observations of the world ocean surface collected by a variety of ships and at distributing quality controlled datasets. At present time the variables considered by GOSUD are temperature and salinity. The GOSUD data are mostly collected using thermosalinographs (TSG) installed on research vessels, on commercial ships and in some cases on sailing exploration ships. GOSUD manages both near-real time (RT and NRT) data and delayed mode (DM-reprocessed) data. The GOSUD GDAC is hosted by the Coriolis data centre (France) and a back-up (permanent archived) is performed on a daily basis by NCEIS (NOAA's National Centers for Environmental Information).

The SDC_GLO_CLIM_Dens product contains global monthly climatological estimates of in situ density using Temperature and Salinity from profiling floats contained in the World Ocean Data 18 (WOD18) database. The profiles were first quality controlled with a Nonlinear Quality control procedure. The climatology considers observations from surface to 2000 m for the time period 2003-2017. Density profiles are computed using UNESCO 1983 (EOS 80) equation from in situ temperature, salinity and pressure measurements by the PFL. Only profiles with both T,S values were used. The gridded fields are computed using DIVAnd (Data Interpolating Variational Analysis) version 2.3.1.

The SDC_GLO_CLIM_O2_AOU product contains two different monthly climatology for dissolved Oxygen and Apparent Oxygen Utilization, SDC_GLO_CLIM_O2 and SDC_GLO_CLIM_AOU respectively from the World Ocean Data (WOD) database. Only basic quality control flags from the WOD are used. The first climatology, SDC_GLO_CLIM_O2, considers Dissolved Oxygen profiles casted together with temperature and salinity from CTD, Profiling Floats (PFL) and Ocean Station Data (OSD) for time duration 2003 to 2017. The second climatology, SDC_GLO_CLIM_AOU, apparent Oxygen utilization, is computed as a difference of dissolved oxygen and saturation O2 profiles. The gridded fields are computed using DIVAnd (Data Interpolating Variational Analysis) version 2.3.1.