No abstract

Sea surface salinity (SSS) measurements from the Aquarius/SAC‐D satellite during September–December 2011 provide the first satellite observations of the salinity structure of tropical instability waves (TIWs) in the Pacific. The related SSS anomaly has a magnitude of approximately ±0.5 PSU. Different from sea surface temperature (SST) and sea surface height anomaly (SSHA) where TIW‐related propagating signals are stronger a few degrees away from the equator, the SSS signature of TIWs is largest near the equator in the eastern equatorial Pacific where salty South Pacific water meets the fresher Inter‐tropical Convergence Zone water. The dominant westward propagation speed of SSS near the equator is approximately 1 m/s. This is twice as fast as the 0.5 m/s TIW speed widely reported in the literature, typically from SST and SSHA away from the equator. This difference is attributed to the more dominant 17‐day TIWs near the equator that have a 1 m/s dominant phase speed and the stronger 33‐day TIWs away from the equator that have a 0.5 m/s dominant phase speed. The results demonstrate the important value of Aquarius in studying TIWs.

regions of the Pacific and Indian Oceans where the interannual variability of the ensemble mean exceeds ensemble spread, indicating that OHC variations are well-constrained by the available observations over the period [1993][1994][1995][1996][1997][1998][1999][2000][2001][2002][2003][2004][2005][2006][2007][2008][2009]. At deeper levels, the ORAs are less well-constrained by observations with the largest differences across the ensemble mostly associated with areas of high eddy kinetic energy, such as the Southern Ocean and boundary current regions. Spatial patterns of OHC change for the period 1997-2009 show good agreement in the upper 300 m and are characterized by a strong dipole pattern in the Pacific Ocean. There is less agreement in the patterns of change at deeper levels, potentially linked to differences in the representation of ocean dynamics, such as water mass formation processes. However, the Atlantic and Southern Oceans Abstract Accurate knowledge of the location and magnitude of ocean heat content (OHC) variability and change is essential for understanding the processes that govern decadal variations in surface temperature, quantifying changes in the planetary energy budget, and developing constraints on the transient climate response to external forcings. We present an overview of the temporal and spatial characteristics of OHC variability and change as represented by an ensemble of dynamical and statistical ocean reanalyses (ORAs). Spatial maps of the 0-300 m layer show large This paper is a contribution to the special issue on Ocean estimation from an ensemble of global ocean reanalyses, consisting of papers from the Ocean Reanalyses Intercomparsion Project (ORAIP), coordinated by CLIVAR-GSOP and GODAE OceanView. The special issue also contains specific studies using single reanalysis systems. The current work emphasizes the need to better observe the deep ocean, both for providing observational constraints for future ocean state estimation efforts and also to develop improved models and data assimilation methods.

No abstract

The long-term estimation of fresh water inflow to coastal bays is important for understanding and managing estuarine coastal ecosystems. The Texas Water Development Board (TWDB) has estimated the total fresh water inflow to bays in Texas using the TxRR (Texas Rainfall-Runoff) model, which is a simple rainfall-runoff relation model. Recently, TWDB requested to develop and apply the SWAT model using up-to-date technologies for estimating inflow to the bays. Two watersheds were selected for a pilot study; one represents an urbanized watershed draining into Galveston Bay (Galveston watershed) and the other represents a rural watershed draining into Matagorda Bay (Matagorda watershed). Two separate SWAT models were developed, one for each watershed. Weather data from weather stations were enhanced and adjusted using NEXRAD (Next Generation Radar) precipitation data. Model calibration and validation was conducted using daily flow observations from USGS stream gage stations (gaged) and the same parameter settings were applied to the rest of the watersheds (ungaged). The total fresh water inflow to the bays by the SWAT model was compared to the estimation by the TxRR model. The daily streamflow calibration at each gage station showed an acceptable coefficient of determination (r 2) ranging from 0.496 to 0.736 with Nash-Sutcliffe coefficient (NS) ranging from 0.372 to 0.643. The correlation and NS for model validation, however, did not show a good agreement and the possible explanation can be applying recent landuse data for model runs for earlier years. The monthly streamflow estimation showed much better agreement between observed and modeled flows; r 2 for calibration ranged from 0.647 to 0.916 and NS ranged from 0.613 to 0.941. The correlation for validation ranged from 0.485 to 0.694 for r 2 and from 0.461 to 0.772 for NS. The comparison of the SWAT and TxRR models' estimation showed a good agreement in monthly total inflow to the bays. The coefficient of determination between the monthly estimations in the Galveston and Matagorda watersheds by the two models was 0.948 and 0.900, respectively.