The relationships between Pacific and Atlantic Ocean sea surface temperatures and Colombian streamflow variability

SummaryAn evaluation of Pacific and Atlantic Ocean sea surface temperatures (SSTs) and Colombian streamflow was performed to identify coupled regions of SST and Colombian streamflow variability. Applying the Singular Value Decomposition (SVD) statistical method, SSTs (and Colombian streamflow for 10 stations) were evaluated for (a) the Pacific Ocean, (b) the Atlantic Ocean, and (c) the combined Pacific and Atlantic Ocean for a 41 year period of record (1960–2000). A lead-time approach was adopted such that spring–summer seasonal (April through September) SSTs were evaluated with streamflow for the following calendar-year (January through December). The El Niño-Southern Oscillation (ENSO) has been acknowledged in previous research efforts as an influence of Colombian streamflow. The ENSO signal identified that warmer (cooler) equatorial SSTs resulted in lesser (greater) streamflow. In general, the use of predefined published indices, such as ENSO, is appealing for water managers and forecasters. However, the utilization of SSTs for entire regions (Pacific and Atlantic Oceans) eliminates any spatial bias as to which oceanic SST region (or regions) impact hydrology. This will assist in the identification of regions that may not be represented in existing indices and could lead to improved forecasting. The SVD 1st temporal expansion series of Pacific (and the combined Pacific and Atlantic) Ocean SSTs and streamflow for several stations resulted in correlation values greater than that of well known climate indices (e.g., ENSO), which could result in improved streamflow predictability.