Did the Beaufort Scale or the Wind Climate Change?

Peterson, Ernest W.; Hasse, Lutz

doi:10.1175/1520-0485(1987)017<1071:dtbsot>2.0.co;2

Cited by 48 publications

(36 citation statements)

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“…Whereas some early studies argued possible errors in wind estimation methods and the equipment used for direct measurements (Peterson and Hasse 1987;Ramage 1987;Wright 1988;Cardone et al 1990), other research based on observed data and modelling outcomes (Hsieh and Boer 1992;Clarke and Lebedev 1996;Vecchi et al 2006) directly suggest a potential decline of the Humboldt upwelling system. Clarke and Lebedev (1996), using observational data of surface atmospheric pressure as a proxy for wind stress, identified weakening episodes of the equatorial trade winds in the Pacific during the 20th Century, especially from 1960.…”

Section: Introductionmentioning

confidence: 99%

The future of coastal upwelling in the Humboldt current from model projections

Oyarzún

Brierley

2018

Clim Dyn

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The Humboldt coastal upwelling system in the eastern South Pacific ocean is one of the most productive marine ecosystems in the world. A weakening of the upwelling activity could lead to severe ecological impacts. As coastal upwelling in eastern boundary systems is mainly driven by wind stress, most studies so far have analysed wind patterns change through the 20th and 21st Centuries in order to understand and project the phenomenon under specific forcing scenarios. Mixed results have been reported, and analyses from General Circulation Models have suggested even contradictory trends of wind stress for the Humboldt system. In this study, we analyse the ocean upwelling directly in 13 models contributing to phase 5 of the Coupled Model Intercomparison Project (CMIP5) in both the historical simulations and an extreme climate change scenario (RCP8.5). The upwelling is represented by the upward ocean mass flux, a newly-included variable that represents the vertical water transport. Additionally, wind stress, ocean stratification, Ekman layer depth and thermocline depth were also analysed to explore their interactions with coastal upwelling throughout the period studied. The seasonal cycle of coastal upwelling differs between the Northern and Southern Humboldt areas. At lower latitudes, the upwelling season spans most of the autumn, winter and spring. However, in the Southern Humboldt area the upwelling season takes place in spring and the summertime with downwelling activity in winter. This persists throughout the Historical and RCP8.5 simulations. For both the Northern and Southern Humboldt areas an increasing wind stress is projected. However, different trends of upwelling intensity are observed away from the sea surface. Whereas wind stress will continue controlling the decadal variability of coastal upwelling on the whole ocean column analysed (surface to 300 m depth), an increasing disconnect with upwelling intensity is projected below 100 m depth throughout the 21st Century. This relates to an intensification of ocean stratification under global warming as shown by the sea water temperature profiles. Additionally, a divergence between the Ekman layer and thermocline depths is also evidenced. Given the interaction of upwelled nutrients and microscopic organisms essential for fish growth, a potential decline of coastal upwelling at depth could lead to unknown ecological and socio-economical effects.

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Section: Introductionmentioning

confidence: 99%

The future of coastal upwelling in the Humboldt current from model projections

Oyarzún

Brierley

2018

Clim Dyn

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“…This research is carried out on a variety of both temporal and spatial scales. Thus, a part of the research is dedicated to global wind and waves climate (Peterson and Hasse, 1987;Sterl et al, 1998). However, more or less regional hindcast studies prevail in this field, e.g.…”

Section: Introductionmentioning

confidence: 99%

Wind waves in the Black Sea: results of a hindcast study

Архипкин

Gippius

Колтерманн

et al. 2014

Nat. Hazards Earth Syst. Sci.

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Abstract. In this study we describe the wind wave fields in the Black Sea. The general aims of the work were the estimation of statistical wave parameters and the assessment of interannual and seasonal wave parameter variability. The domain of this study was the entire Black Sea. Wave parameters were calculated by means of the SWAN wave model on a 5 × 5 km rectangular grid. Initial conditions (wind speed and direction) for the period between 1949 and 2010 were derived from the NCEP/NCAR reanalysis. According to our calculations the average significant wave height on the Black Sea does not exceed 0.7 m. Areas of most significant heavy sea are the southwestern and the northeastern parts of the sea as expressed in the spatial distribution of significant wave heights, wave lengths and periods. Besides, long-term annual variations of wave parameters were estimated. Thus, linear trends of the annual total duration of storms and of their quantity are nearly stable over the hindcast period. However, an intensification of storm activity is observed in the 1960s-1970s.

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“…This Beaufort Equivalent Scale, known as WMO1100, relates wind speed to the characteristics of the sea state, and is still used today (WMO, 1970). Use of wind speeds from VOS for climate trend analysis before 1946 is problematic, as wind reports evolved from those derived from the amount of sail a ship could carry to those derived from observations of the sea state (Peterson and Hasse, 1987;Ramage, 1987;Cardone et al, 1990).…”

Section: Introductionmentioning

confidence: 99%

“…Peterson and Hasse (1987); Ramage (1987), and Cardone et al (1990) concluded that the increasing trend in archived ship wind speeds since the 1940s was due to the increasing proportion of measured ship wind reports.…”

Section: Introductionmentioning

confidence: 99%

Trends in ship wind speeds adjusted for observation method and height

Thomas

Kent

Swail

et al. 2007

Intl Journal of Climatology

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Globally averaged wind speeds from archived ship reports show an increasing trend since the 1940s, which previous studies attributed to the gradual shift from visually estimated to anemometer-measured winds, and an increase in mean anemometer height. To test this hypothesis, adjustments to account for these changes were applied to individual ship wind observations in the International Comprehensive Ocean-Atmosphere Data Set (ICOADS). Annual means calculated from adjusted reports were compared to reanalysis near-surface winds in consistently well-sampled regions for the period 1958-2002.The adjustments to individual ship wind reports for known biases improve the homogeneity over the entire period and remove trends, prior to the early 1980s. However, for the 21-year period 1982-2002, trends remain in the annual mean spatially averaged adjusted winds, of 0.4 ms −1 decade −1 (6% decade −1 ) for estimated speeds, and of 0.2 ms −1 decade −1 (3% decade −1 ) for measured speeds. In contrast, co-located reanalysis near-surface wind speeds show little change, 1% decade −1 or less. Anemometers were installed on increasing numbers of ships during the period of study, even as many of these ships continued to report estimated winds. Part of the trend in estimated wind speeds is probably spurious, most likely a result of observers being increasingly influenced by readings from anemometers located well above 10-m. This influence is indicated by the gradual reduction in the tendency to underestimate nighttime marine winds. Results confirm earlier findings that reanalysis near-surface winds were biased low. The paper summarizes methods that could be employed to account for remaining inhomogeneities and thereby improve the quality of the marine wind climate record.

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Did the Beaufort Scale or the Wind Climate Change?

Cited by 48 publications

References 0 publications

The future of coastal upwelling in the Humboldt current from model projections

The future of coastal upwelling in the Humboldt current from model projections

Wind waves in the Black Sea: results of a hindcast study

Trends in ship wind speeds adjusted for observation method and height

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