A Coupled Ocean Physics‐Biology Modeling Study on Tropical Instability Wave‐Induced Chlorophyll Impacts in the Pacific

2018 ◽  
Vol 123 (8) ◽  
pp. 5160-5179 ◽  
Author(s):  
Feng Tian ◽  
Rong‐Hua Zhang ◽  
Xiujun Wang
Keyword(s):  
Instability Wave ◽  
The Pacific ◽  
Ocean Physics ◽  
Wave Induced ◽  
Modeling Study

scholarly journals Near-Surface Shear Flow in the Tropical Pacific Cold Tongue Front*

2009 ◽  
Vol 39 (5) ◽  
pp. 1200-1215 ◽  
Author(s):  
Meghan F. Cronin ◽  
William S. Kessler
Keyword(s):  
Turbulent Viscosity ◽  
Instability Wave ◽  
Surface Currents ◽  
Cold Tongue ◽  
Surface Shear ◽  
Near Surface ◽  
The Pacific ◽  
Geostrophic Shear ◽  
Moored Current Meters ◽  
The Tropical Pacific

Abstract Near-surface shear in the Pacific cold tongue front at 2°N, 140°W was measured using a set of five moored current meters between 5 and 25 m for nine months during 2004–05. Mean near-surface currents were strongly westward and only weakly northward (∼3 cm s−1). Mean near-surface shear was primarily westward and, thus, oriented to the left of the southeasterly trades. When the southwestward geostrophic shear was subtracted from the observed shear, the residual ageostrophic currents relative to 25 m were northward and had an Ekman-like spiral, in qualitative agreement with an Ekman model modified for regions with a vertically uniform front. According to this “frontal Ekman” model, the ageostrophic Ekman spiral is forced by the portion of the wind stress that is not balanced by the surface geostrophic shear. Analysis of a composite tropical instability wave (TIW) confirms that ageostrophic shear is minimized when winds blow along the front, and strengthens when winds blow oblique to the front. Furthermore, the magnitude of the near-surface shear, both in the TIW and diurnal composites, was sensitive to near-surface stratification and mixing. A diurnal jet was observed that was on average 12 cm s−1 stronger at 5 m than at 25 m, even though daytime stratification was weak. The resulting Richardson number indicates that turbulent viscosity is larger at night than daytime and decreases with depth. A “generalized Ekman” model is also developed that assumes that viscosity becomes zero below a defined frictional layer. The generalized model reproduces many of the features of the observed mean shear and is valid both in frontal regions and at the equator.

scholarly journals Finding the missing stratospheric Br<sub>y</sub>: a global modeling study of CHBr<sub>3</sub> and CH<sub>2</sub>Br<sub>2</sub>

2009 ◽  
Vol 9 (6) ◽  
pp. 23623-23664
Author(s):  
Q. Liang ◽  
R. S. Stolarski ◽  
S. R. Kawa ◽  
J. E. Nielsen ◽  
J. M. Rodriguez ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Large Scale ◽  
Climate Model ◽  
Airborne Measurements ◽  
Earth Observing System ◽  
Tropical Tropopause ◽  
The Pacific ◽  
Emission Estimate ◽  
High Concentrations ◽  
Modeling Study

Abstract. Recent in situ and satellite measurements suggest a contribution of ~5 pptv to stratospheric inorganic bromine from short-lived bromocarbons. We conduct a modeling study of the two most important short-lived bromocarbons, bromoform (CHBr3) and dibromomethane (CH2Br2), with the Goddard Earth Observing System Chemistry Climate Model (GEOS CCM) to account for this missing stratospheric bromine. We derive a "top-down" emission estimate of CHBr3 and CH2Br2 using airborne measurements in the Pacific and North American troposphere and lower stratosphere (LS) obtained during previous NASA aircraft campaigns. Our emission estimate suggests that to reproduce the observed concentrations in the free troposphere, a global oceanic emission of 425 Gg Br yr−1 for CHBr3 and 57 Gg Br yr−1 for CH2Br2 is needed, with 60% of emissions from open ocean and 40% from coastal regions. Although our simple emission scheme assumes no seasonal variations, the model reproduces the observed seasonal variations of the short-lived bromocarbons with high concentrations in winter and low concentrations in summer. This indicates that the seasonality of short-lived bromocarbons is largely due to seasonality in their chemical loss and transport. The inclusion of CHBr3 and CH2Br2 contributes ~5 pptv bromine throughout the stratosphere. Both the source gases and inorganic bromine produced from the source gas degradation (BryVSLS) in the troposphere are transported into the stratosphere, and are equally important. Inorganic bromine accounts for half (2.5 pptv) of the bromine from the inclusion of CHBr3 and CH2Br2 near the tropical tropopause and its contribution rapidly increases to ~100% as altitude increases. More than 85% of the wet scavenging of BryVSLS occurs in large-scale precipitation below 500 hPa and BryVSLS in the stratosphere is not sensitive to convection.

Assessing feedback of tropical instability wave-induced wind stress perturbations in the equatorial Pacific

2018 ◽  
Vol 39 (3) ◽  
pp. 1634-1643 ◽  
Author(s):  
Yanzhou Wei ◽  
Yuhua Pei ◽  
Xianbiao Kang
Keyword(s):  
Wind Stress ◽  
Equatorial Pacific ◽  
Instability Wave ◽  
Wave Induced

A Positive Feedback Onto ENSO Due to Tropical Instability Wave (TIW)‐Induced Chlorophyll Effects in the Pacific

2019 ◽  
Vol 46 (2) ◽  
pp. 889-897
Author(s):  
Feng Tian ◽  
Rong‐Hua Zhang ◽  
Xiujun Wang
Keyword(s):  
Positive Feedback ◽  
Instability Wave ◽  
The Pacific

scholarly journals Effects of Irrigation on Water, Carbon, and Nitrogen Budgets in a Semiarid Watershed in the Pacific Northwest: A Modeling Study

2020 ◽  
Vol 12 (9) ◽  
Author(s):  
Bowen Zhu ◽  
Maoyi Huang ◽  
Yanyan Cheng ◽  
Xianhong Xie ◽  
Ying Liu ◽  
...  
Keyword(s):  
Pacific Northwest ◽  
Nitrogen Budgets ◽  
Carbon And Nitrogen ◽  
The Pacific ◽  
Modeling Study
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