On the Existence of Atmospheric Vortices Downwind of Hawaii during the HAMEC Project

Nickerson, Everett C.; Dias, Michael A.

doi:10.1175/1520-0450(1981)020<0868:oteoav>2.0.co;2

Cited by 22 publications

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“…The lee vortices and reverse flow appear in the ship‐based climatology of Patzert (), extending to roughly 156.5°W, though it is not clear how many observations Patzert used. The lee vortices and reverse flow also appear in aircraft observations taken at 45‐m height (Nickerson & Dias, ) and at 450‐m height (Smith & Grubisic, ); the aircraft observations show the lee vortices extending to roughly 157°W.…”

Section: Systematic Scatterometer Wind Errorsmentioning

confidence: 75%

“…HRCM also shows a local minimum in surface pressure for the northern vortex, with an amplitude of 0.1 hPa. The agreement between the ICOADS ship-based winds, HRCM model winds, and aircraft observations (Nickerson & Dias, 1981;Smith & Grubisic, 1993) suggests that the lee vortices are real and that the scatterometer winds contain a systematic error.…”

Section: Hawaii's Big Islandmentioning

confidence: 77%

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Systematic Scatterometer Wind Errors Near Coastal Mountains

Kilpatrick

Xie

Tokinaga

et al. 2019

Earth and Space Science

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Satellite scatterometers provide the only regular observations of surface wind vectors over vast swaths of the world oceans, including coastal regions, which are of great scientific and societal interest but still present challenges for remote sensing. Here we demonstrate systematic scatterometer wind errors near Hawaii's Big Island: Two counter‐rotating lee vortices, which are clear in the International Comprehensive Ocean‐Atmosphere Data Set ship‐based wind climatology and in aircraft observations, are absent in the Jet Propulsion Laboratory and Remote Sensing Systems scatterometer wind climatologies. We demonstrate similar errors in the representation of transient Catalina Eddy events in the Southern California Bight. These errors likely arise from the nonuniqueness of scatterometer wind observations, that is, an “ambiguity removal” is required during processing to select from multiple wind solutions to the geophysical model function. We discuss strategies to improve the ambiguity selection near coastal mountains, where small‐scale wind reversals are common.

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Section: Systematic Scatterometer Wind Errorsmentioning

confidence: 75%

Section: Hawaii's Big Islandmentioning

confidence: 77%

Systematic Scatterometer Wind Errors Near Coastal Mountains

Kilpatrick

Xie

Tokinaga

et al. 2019

Earth and Space Science

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“…However, there had been little observational evidence of formation of the vortex streets associated with the island of Hawaii (Chopra, 1973). The first in situ observational evidence that indicated the existence of low-level atmospheric eddies downwind of the island of Hawaii was presented by Nickerson and Dias (1981) [hereafter referred to as ND] . We note the atmospheric conditions utilized in our current experiment are fairly similar to observed situations described by ND.…”

Section: B Initial and Boundary Conditionsmentioning

confidence: 99%

A Three-Dimensional Simulation of Airflow and Orographic Rain over the Island of Hawaii

Ueyoshi

Han

1991

Journal of the Meteorological Society of Japan

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A three-dimensional mesoscale numerical model is presented, designed with the capability of simulating the airflow and orographically-induced rain in the presence of steep irregular terrain. The model utilizes a fourth-order accurate version of Arakawa's potential enstrophy and total energy conserving scheme to improve the simulation of nonlinear aspects of the airflow over steep topography, along with an adiabatic reference atmosphere to reduce the effects of orographic truncation errors. The precipitation processes are represented by large-scale condensation.The model is applied to the island of Hawaii. The results of a 24-h simulation indicate the model is generally successful in reproducing leeward eddies depicted in the composite surface airflow patterns.A nondimensional analysis of vortex parameters suggests that the simulated vortex pattern is an atmospheric analog of the Karman vortex street and compares favorably with an observed case of Hawaii vortices. Spatial distribution of simulated rainfall is also generally in good agreement with observations. However, the lack of precipitation in the lowland along the windward as well as leeward coast is apparent.The excess rainfall over the southern peninsula suggests the need for an finer grid mesh to improve representation of the effects of subgrid-scale mountain forcing. An application of the model to regional climate modeling through the use of large-scale objective analyses is also discussed.

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“…With mountain heights (Ͼ4000 m) well above the typical height of trade-wind inversion (ϳ2 km), the trade-wind inversion serves as a lid forcing the low-level flow on the windward side to split and move around the island (Leopold 1949;Chen and Feng 2001). The large wake off the leeside Kona coast with two large counterrotating vortices (Patzert 1969;Nickerson and Dias, 1981;Smith and Grubišić 1993) occurs in the flow regime because of the inability of the flow to move over the mountaintops of Mauna Loa and Mauna Kea (Schär and Smith 1993). In addition to the large wake off the Kona coast, a small wake also occurs off the leeside coast of the Kohala Mountains in northwest Hawaii (Smith and Grubišić 1993).…”

Section: Introductionmentioning

confidence: 99%

“…In the past, many numerical studies for the island of Hawaii have been conducted (Nickerson 1979;Fett and Bury, 1981;Smolarkiewicz et al 1988;Rasmussen et al 1989;Ueyoshi and Han 1991;Reisner and Smolarkiewicz 1994;and others); however, the diurnal thermal forcing from the land surface was crudely estimated in these studies. Feng and Chen (2001) used the fifth-generation Pennsylvania State University-National Center for Atmospheric Research (NCAR) Mesoscale Model (MM5), version 1, to successfully simulate the nocturnal regime on the windward side of the island of Hawaii with the land surface specified as tropical rain forest over the entire island.…”

Section: Introductionmentioning

confidence: 99%

Effects of Trade-Wind Strength and Direction on the Leeside Circulations and Rainfall of the Island of Hawaii

Yang

Chen

Fujioka³

2008

Monthly Weather Review

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The leeside circulations and weather of the island of Hawaii were studied from the fifth-generation Pennsylvania State University-NCAR Mesoscale Model (MM5) land surface model simulations for eight strong (ϳ7.9 m s Ϫ1 ) and eight weak (ϳ5.2 m s Ϫ1 ) trade-wind days and for five days with southeasterly trades (ϳ7.1 m s Ϫ1 ) during summer 2004. The objective is to investigate the effects of trade-wind strength and directions on the leeside circulations and rainfall and the modification of these effects by the land surface thermal forcing. For the small wake on the lee side of the Kohala Mountains (1700 m, lower than the trade-wind inversion at 2000 m) over northern Hawaii, the hydraulic jump is present with stronger downslope winds and warmer and drier conditions on the lee side and a weaker westerly reversed flow offshore when trades are stronger. In contrast, the westerly reversed flow along the large wake axis off the central Kona leeside coast (behind massive mountains with tops Ͼ4000 m) is 1-1.5 m s Ϫ1 stronger and 200-300 m deeper with higher moisture content when trades are stronger. Over the Kona slopes, the daytime thermally direct circulation cell is more significant when trades are stronger because of descending airflow aloft with less cloudiness. In the evening, the convergence between the westerly reversed flow offshore along the wake axis and the offshore/katabatic flow in the Kona coastal region is more significant with higher evening rainfall when trades are stronger. During the day, the lee side of the Kohala Mountains is characterized by a reversed flow (ϳ4 m s Ϫ1 ) merging with sea-breeze circulations along the coast. When trades are stronger, the convergence between the anabatic winds and the descending flow from the upper slopes is greater. However, the simulated cloud water there is less under strong trades because of warmer and drier conditions due to significant adiabatic descent in the lee. At night, when trades are stronger, the combined downslope/katabatic flow prevails without a reversed flow offshore. Under a southeasterly trade-wind flow with a lower trade-wind inversion (1.5 km), the westerly reversed flow is shallower; the adiabatic descent aloft on the southwestern leeside areas is more significant with warmer temperatures (0.5 K), a larger negative potential vorticity maximum [0.2 potential vorticity units (PVU), 1 PVU ϭ 10 Ϫ6 K m 2 s Ϫ1 kg Ϫ1 ], and a more pronounced anticyclonic vortex offshore. The westerly reversed flow off the Kona coast shifts northward.

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On the Existence of Atmospheric Vortices Downwind of Hawaii during the HAMEC Project

Cited by 22 publications

References 0 publications

Systematic Scatterometer Wind Errors Near Coastal Mountains

Systematic Scatterometer Wind Errors Near Coastal Mountains

A Three-Dimensional Simulation of Airflow and Orographic Rain over the Island of Hawaii

Effects of Trade-Wind Strength and Direction on the Leeside Circulations and Rainfall of the Island of Hawaii

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