Temperature variability and trends in the UT-LS over a subtropical site: Reunion (20.8° S, 55.5° E)

Bègue, Nelson; Benchérif, Hassan; Sivakumar, Venkataraman; Kirgis, Guillaume; Mzé, Nahoudha; Bellevue, Jimmy Leclair de

doi:10.5194/acp-10-8563-2010

Cited by 18 publications

(27 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To identify the impact of the different modes of variability affecting the SWIO on the lightning activity, we used a statistical model called "Trend-Run" (Bencherif et al, 2006;Bègue et al, 2010). Previously, temperature trends and variations over 2 subtropical sites (Durban and La Réunion) have been studied with this model using monthly mean radiosonde temperature profiles (for the periods 1980-2001 and 1993-2008, respectively).…”

Section: Variabilitymentioning

confidence: 99%

“…Recent results by Morioka et al (2010) revealed that IOD acts as a major climate mode in the SWIO. Thus, the IOD has been included (Bègue et al, 2010) using the Dipole Mode Index (Behera and Yamagata, 2003) defined as the difference in SST between the western and eastern tropical Indian Ocean. Since the MJO is the dominant intra-seasonal mode of variability in the tropics (Zhang, 2005), this forcing has also been added in Trend-Run.…”

Section: Variabilitymentioning

confidence: 99%

“…More details on Trend-Run are available in Bencherif et al (2006) and Bègue et al (2010). In order to investigate the lightning activity variability in the SWIO, the initial area was subdivided into 10 • ×10 • bins, and the WWLLN strokes were counted to get monthly time series for each box.…”

Section: Variabilitymentioning

confidence: 99%

See 2 more Smart Citations

A lightning climatology of the South-West Indian Ocean

Bovalo

Barthe

Bègue

2012

Nat. Hazards Earth Syst. Sci.

Self Cite

View full text Add to dashboard Cite

The SWIO is characterized by a wet season (November to April) and a dry season (May to October). As one could expect, lightning activity is more intense during the wet season as the Inter Tropical Convergence Zone (ITCZ) is present over all the basin. Flash density is higher over land in November-December-January with values reaching 3-4 fl km −2 yr −1 over Madagascar. During the dry season, lightning activity is quite rare between 10 • S and 25 • S. The Mascarene anticyclone has more influence on the SWIO resulting in shallower convection. Lightning activity is concentrated over ocean, east of South Africa and Madagascar.A statistical analysis has shown that El Niño-Southern Oscillation mainly modulates the lightning activity up to 56.8 % in the SWIO. The Indian Ocean Dipole has a significant contribution since ∼ 49 % of the variability is explained by this forcing in some regions. The Madden-Julian Oscillation did not show significative impact on the lightning activity in our study.

show abstract

Section: Variabilitymentioning

confidence: 99%

Section: Variabilitymentioning

confidence: 99%

See 1 more Smart Citation

A lightning climatology of the South-West Indian Ocean

Bovalo

Barthe

Bègue

2012

Nat. Hazards Earth Syst. Sci.

Self Cite

View full text Add to dashboard Cite

show abstract

“…1) considers the main parameters such as annual (AC) and semi-annual cycles Ann. Geophys., 36, 301-310, 2018 www.ann-geophys.net/36/301/2018/ (SAC), QBO (quasi-biennial oscillation), ENSO (El Niño-Southern Oscillation), and the 11-year cycle (Sunspot Number), in addition to a residual term ε, assuming a consistent trend (Bègue et al, 2010). In this way, the contribution that each of these cycles or oscillations makes to the temperature variance may be estimated.…”

Section: Trend-run Modelmentioning

confidence: 99%

Mesopause region temperature variability and its trend in southern Brazil

et al. 2018

View full text Add to dashboard Cite

Abstract. Nowadays, the study of the upper atmosphere is increasing, mostly because of the need to understand the patterns of Earth's atmosphere. Since studies on global warming have become very important for the development of new technologies, understanding all regions of the atmosphere becomes an unavoidable task. In this paper, we aim to analyze the temperature variability and its trend in the mesosphere and lower thermosphere (MLT) region during a period of 12 years (from 2003 to 2014). For this purpose, three different heights, i.e., 85, 90 and 95 km, were focused on in order to investigate the upper atmosphere, and a geographic region different to other studies was chosen, in the southern region of Brazil, centered in the city of Santa Maria, RS (29 • 41 02 S; 53 • 48 25 W). In order to reach the objectives of this work, temperature data from the SABER instrument (Sounding of the Atmosphere using Broadband Emission Radiometry), aboard NASA's Thermosphere Ionosphere Mesosphere Energetics Dynamics (TIMED) satellite, were used. Finally, two cases were studied related to distinct grids of latitude/longitude used to obtain the mean temperature profiles. The first case considered a grid of 20 • × 20 • lat/long, centered in Santa Maria, RS, Brazil. In the second case, the region was reduced to a size of 15 • × 15 • in order to compare the results and discuss the two cases in terms of differences or similarities in temperature trends. Observations show that the size of the geographical area used for the average temperature profiles can influence the results of variability and trend of the temperature. In addition, reducing the time duration of analyses from 24 to 12 h a day also influences the trend significantly. For the smaller geographical region (15 • × 15 • ) and the 12 h daily time window (09:00-21:00 UT) it was found that the main contributions for the temperature variability at the three heights were the annual and semi-annual cycles and the solar flux influence. A smaller trend (−0.02 ± 0.16 % decade −1 ) was found at 90 km height and small positive trends (0.58 ± 0.26 % and 0.41 ± 0.19 % decade −1 ) were found at altitudes of 85 and 95 km, respectively.. Keywords. Atmospheric composition and structure (middle atmosphere -composition and chemistry; pressure density and temperature) -meteorology and atmospheric dynamics (climatology)

show abstract

“…While interest to some degree has moved from the tropical to the extratropical UTLS region (e.g. Bègue et al, 2010), the polar regions, reviewed by e.g. Highwood et al (2000), are still poorly covered.…”

Section: Introduction and Data Sourcesmentioning

confidence: 99%

Tropopause height at 78° N 16° E: average seasonal variation 2007–2010

Hall¹,

Hansen

Sigernes³

et al. 2011

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract. We present a seasonal climatology of tropopause altitude for 78 • N 16 • E derived from observations 2007-2010 by the SOUSY VHF radar on Svalbard. The spring minimum occurs one month later than that of surface air temperature and instead coincides with the maximum in ozone column density. This confirms similar studies based on radiosonde measurements in the arctic and demonstrates downward control by the stratosphere. If one is to exploit the potential of tropopause height as a metric for climate change at high latitude and elsewhere, it is imperative to observe and understand the processes which establish the tropopause -an understanding to which this study contributes.

show abstract

Temperature variability and trends in the UT-LS over a subtropical site: Reunion (20.8° S, 55.5° E)

Cited by 18 publications

References 47 publications

A lightning climatology of the South-West Indian Ocean

A lightning climatology of the South-West Indian Ocean

Mesopause region temperature variability and its trend in southern Brazil

Tropopause height at 78° N 16° E: average seasonal variation 2007–2010

Contact Info

Product

Resources

About