Wednesday, October 2, 2013


While on station for our final CTD cast, what had been ominously dark skies in the distance quickly became a torrential downpour with winds gusting to 35 kts and a temperature drop of 5 deg C.  The wind didn't blow hard enough or long enough to markedly alter the sea state, but for a few minutes there was white spray flying everywhere.

Instruments on Endeavor measure wind speed, temperature, barometric pressure, and solar radiation every second.  Shown below (courtesy Ben Hodges) are one-minute-averaged wind speed from three different sensors (red, green, black) and air temperature (blue).  The wind speed increased by almost 20 kts in under 2 minutes.

The strong winds didn't last long and we were able to recover our CTD and deploy an Argo float without difficulty.  Interestingly, all of the rain and wind and waves only resulted in a 0.1 drop in salinity while on station, even at the shallow depths measured by our salinity snake.  By the time we had steamed 10 km south surface salinities had returned to pre-rain levels.

We're still a good distance from the reported center of Tropical Storm Jerry (600 km to our west -- see the orange circle in the visible satellite image below).  Endeavor is located in the blue square.  You can see some obvious spiral rain bands associated with Jerry that extend this far east.  Perhaps this explains the cloudy blob we're under at the moment.

Fortunately, the remainder of our survey work will take us quickly south and west, away from the clouds and rain.  We may see some larger swell over the next few days but should be back under sunny skies by tomorrow.

Although major over-the-side work is now complete we have just reached the halfway point of this voyage.  There is still a lot of data to download from the moored instruments, salinity samples to run, Argo floats to deploy, a buoy to recover, conference abstracts to write, papers to revise, blogs to post, and approximately 34 meals (and 22 between-meal snacks) to consume.  We'll be plenty busy.

The plan for the remainder of this cruise is pretty simple:  (1) Survey the western part of the salinity maximum region (including some interesting filamentary structures evident in numerical model forecasts), (2) Recover the PICO-E surface buoy, and (3) Go home!  

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