کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4533466 | 1325194 | 2009 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
The diapcynal nutrient flux and shear-induced diapcynal mixing in the seasonally stratified western Irish Sea
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موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
زمین شناسی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: The diapcynal nutrient flux and shear-induced diapcynal mixing in the seasonally stratified western Irish Sea The diapcynal nutrient flux and shear-induced diapcynal mixing in the seasonally stratified western Irish Sea](/preview/png/4533466.png)
چکیده انگلیسی
We estimate the diapcynal nitrate flux in the seasonally stratified western Irish Sea using the dissipation method. By comparing the divergence of the reported benthic and diapcynal nitrate fluxes, we are able to explain much of the observed annual summer decline in deep-water nitrate at this location. We then show that the new production, fuelled by the diapcynal nitrate flux, is of a similar magnitude to that associated with the spring bloom. This suggests that the physical processes responsible for the diapcynal nitrate flux will set the limit on new production at this location. High-resolution mid-water column ADCP measurements show an average thermocline gradient Richardson number of 1, thus suggesting episodes of enhanced shear could result in shear instability, and therefore mixing within the thermocline. Bulk shear measurements reveal episodes of enhanced shear in the form of spikes, during which time the bulk shear vector takes the form of a clockwise rotating vector which has a period close to the local inertial period. The episodes of shear spikes are correlated to the wind and are consistent with observations made elsewhere. Estimates of profiles of the rate of dissipation of turbulent kinetic energy, based on microstructure velocity measurements, show that during a shear spike the dissipation rate within the thermocline, and therefore the buoyancy (and nitrate) flux, is enhanced by a factor of 4 when compared to periods with no shear spikes. Intermittent shear spikes are, therefore, an important mechanism for enhancing mixing across the shelf sea seasonal thermocline, and therefore delivery of nitrate to the euphotic zone, at this location.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Continental Shelf Research - Volume 29, Issue 13, 30 June 2009, Pages 1580-1587
Journal: Continental Shelf Research - Volume 29, Issue 13, 30 June 2009, Pages 1580-1587
نویسندگان
Tom P. Rippeth, Phil Wiles, Matt R. Palmer, Jonathan Sharples, Jacqueline Tweddle,