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Kyla Drushka

Senior Oceanographer

Affiliate Assistant Professor, Oceanography

Email

kdrushka@apl.washington.edu

Phone

206-543-6858

Education

BS Physics, McGill University, 2004

PhD Physical Oceanography, Scripps Institution of Oceanography, 2011

Publications

2000-present and while at APL-UW

Extension of the prognostic model of sea surface temperature to rain-induced cool and fresh lenses

Bellenger, H., K. Drushka, W. Asher, G. Reverdin, M. Katsumata, and M. Watanabe, "Extension of the prognostic model of sea surface temperature to rain-induced cool and fresh lenses," J. Geophys. Res., 122, 484-507, doi:10.1002/2016JC012429, 2017.

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1 Jan 2017

The Zeng and Beljaars (2005) sea surface temperature prognostic scheme, developed to represent diurnal warming, is extended to represent rain-induced freshening and cooling. Effects of rain on salinity and temperature in the molecular skin layer (first few hundred micrometers) and the near-surface turbulent layer (first few meters) are separately parameterized by taking into account rain-induced fluxes of sensible heat and freshwater, surface stress, and mixing induced by droplets penetrating the water surface. Numerical results from this scheme are compared to observational data from two field studies of near-surface ocean stratifications caused by rain, to surface drifter observations and to previous computations with an idealized ocean mixed layer model, demonstrating that the scheme produces temperature variations consistent with in situ observations and model results. It reproduces the dependency of salinity on wind and rainfall rate and the lifetime of fresh lenses. In addition, the scheme reproduces the observed lag between temperature and salinity minimum at low wind speed and is sensitive to the peak rain rate for a given amount of rain. Finally, a first assessment of the impact of these fresh lenses on ocean surface variability is given for the near-equatorial western Pacific. In particular, the variability due to the mean rain-induced cooling is comparable to the variability due to the diurnal warming so that they both impact large-scale horizontal surface temperature gradients. The present parameterization can be used in a variety of models to study the impact of rain-induced fresh and cool lenses at different spatial and temporal scales.

Satellite and in situ salinity: Understanding near-surface stratification and sub footprint variability

Boutin, J., and 21 others, including W.E. Asher and K. Drushka, "Satellite and in situ salinity: Understanding near-surface stratification and sub footprint variability," Bull. Am. Meteor. Soc., 97, 1391-1407, doi:10.1175/BAMS-D-15-00032.1, 2016.

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1 Aug 2016

Remote sensing of salinity using satellite-mounted microwave radiometers provides new perspectives for studying ocean dynamics and the global hydrological cycle. Calibration and validation of these measurements is challenging because satellite and in situ methods measure salinity differently. Microwave radiometers measure the salinity in the top few centimeters of the ocean, whereas most in situ observations are reported below a depth of a few meters. Additionally, satellites measure salinity as a spatial average over an area of about 100 x 100 km2. In contrast, in situ sensors provide pointwise measurements at the location of the sensor. Thus, the presence of vertical gradients in, and horizontal variability of, sea surface salinity complicates comparison of satellite and in situ measurements. This paper synthesizes present knowledge of the magnitude and the processes that contribute to the formation and evolution of vertical and horizontal variability in near-surface salinity. Rainfall, freshwater plumes, and evaporation can generate vertical gradients of salinity, and in some cases these gradients can be large enough to affect validation of satellite measurements. Similarly, mesoscale to submesoscale processes can lead to horizontal variability that can also affect comparisons of satellite data to in situ data. Comparisons between satellite and in situ salinity measurements must take into account both vertical stratification and horizontal variability.

Impact of slowdown of Atlantic overturning circulation on heat and freshwater transports

Kelly, K.A., K. Drushka, L. Thompson, D. Le Bars, and E.L. McDonagh, "Impact of slowdown of Atlantic overturning circulation on heat and freshwater transports," Geophys. Res. Lett., 43, 7625-7631, doi:10.1002/2016GL069789, 2016.

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28 Jul 2016

Recent measurements of the strength of the Atlantic overturning circulation at 26°N show a 1 year drop and partial recovery amid a gradual weakening. To examine the extent and impact of the slowdown on basin wide heat and freshwater transports for 2004–2012, a box model that assimilates hydrographic and satellite observations is used to estimate heat transport and freshwater convergence as residuals of the heat and freshwater budgets. Using an independent transport estimate, convergences are converted to transports, which show a high level of spatial coherence. The similarity between Atlantic heat transport and the Agulhas Leakage suggests that it is the source of the surface heat transport anomalies. The freshwater budget in the North Atlantic is dominated by a decrease in freshwater flux. The increasing salinity during the slowdown supports modeling studies that show that heat, not freshwater, drives trends in the overturning circulation in a warming climate.

More Publications

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center
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