Effect of the annular solar eclipse of 15 January 2010 on the lower atmospheric boundary layer over a tropical rural station

Ratnam, M. Venkat; Kumar, Manoj; Basha, Ghouse; Anandan, V. K.; Jayaraman, A.

doi:10.1016/j.jastp.2010.10.009

Cited by 30 publications

(11 citation statements)

References 23 publications

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“…Temperature drop ranged from 2.3°C to 2.7°C with the time lag of 12–14 min from maximum phase of the eclipse have been reported earlier during solar eclipse on 26 March 2006 [ Founda et al , 2007]. Temperature decrease of 5.8°–2.5° was observed with the corresponding increase of 15%–7% in RH over Gadanki (13.51°N, 79.21°E), a tropical rural station, during the eclipse of 15 January 2010 [ Venkat Ratnam et al , 2010]. The time lag between the occurrences of the temperature minimum and the maximum phase of eclipse is considered to be the result of the thermal inertia of the air and the ground [ Fernández et al , 1993b].…”

Section: Resultsmentioning

confidence: 80%

The changes in near‐surface ozone and precursors at two nearby tropical sites during annular solar eclipse of 15 January 2010

et al. 2012

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[1] Studies on the solar eclipse-induced changes in near-surface ozone and its precursors NO x and CO were carried out at two nearby tropical coastal locations, Thumba (very close to the sea) and the Centre for Earth Science Studies (CESS), which is 4.5 km off the Thumba coast and with varying topography, during the annular eclipse of 15 January 2010. The surface ozone decreased by 12 and 13 ppb (35% and 52%) over Thumba and CESS, with the time lag of 40 min and 25 min from the maximum phase of eclipse, respectively, and at CESS, post-eclipse recovery was faster compared to Thumba. No pronounced change was observed in NO x , but CO showed an enhancement toward the ending phase of the eclipse. The diurnal patterns of ozone and their differences at the two sites were strongly dependent on local meteorology, in particular, the mesoscale dynamics and topography. While the temperature decreased by 1.2°C at Thumba, the decrease was almost double ($2.1°C) at CESS. The early fall in temperature caused the early setting in of land-breeze (post-eclipse effect), which in turn triggered an early evening decrease in near-surface ozone compared to the control conditions. The present study points to the role of mesoscale meteorology/dynamics in controlling the evolution of solar eclipse-induced changes in ozone in a relatively clean environment. The chemical box model simulations reproduced these broad features: a percentage decrease and the time lag in surface ozone. The observation of total column ozone showed a decrease and fluctuations, after the eclipse maximum.

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Section: Resultsmentioning

confidence: 80%

The changes in near‐surface ozone and precursors at two nearby tropical sites during annular solar eclipse of 15 January 2010

et al. 2012

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“…() could not detect the eclipse at depths below 10 and 20 cm, whereas Founda et al () and Venkat Ratnam et al . () were able to do so, albeit slightly. The soil characteristics, including its moisture and the coating type, certainly explain these different results.…”

Section: Energy Balance Of the Lawnmentioning

confidence: 99%

“…The influence of the zenithal angle can be clearly seen on the global radiation measured by Venkat Ratnam et al . () during the decreasing phase of the eclipse in the afternoon: the global radiation maximum is clearly reached several minutes before the fourth contact. However, it is not possible to completely exclude an instrumental error.…”

Section: Incoming Solar Radiationmentioning

confidence: 99%

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Effects of the 20 March 2015 solar eclipse in Strasbourg, France

Kastendeuch

Najjar

Colin

et al. 2016

Weather

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On 20 March 2015 a partial solar eclipse occurred at Strasbourg, France, with an obscuration of 72.4%. The consequences of this event were observed under optimal weather conditions with micrometeorological instruments. Among these, the global radiation deficit can be estimated to be of 1.724MJ per horizontal square meter. A modification of the solar spectrum with a greater proportion of photosynthetically active radiation was also observed. The extinction of the solar radiation resulted in a reduction of the net radiation, a sharp decrease in the surface temperatures and a change in all surface heat fluxes.

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“…SODAR is an acoustic sounding system, which is very useful for studying temperature inversions, which cause radio ducts. However, because of low energy and speed, the profiles of SODAR do not reach above 1 km [ Venkat Ratnam et al ., ] which causes the missing of duct layers above 1 km. Apart from the observational data, model data sets may also be used to study the global picture of duct characteristics [ Von Engeln and Teixeira , ].…”

Section: Introductionmentioning

confidence: 99%

Diurnal variation of ducts observed over a tropical station, Gadanki, using high‐resolution GPS radiosonde observations

Manjula¹,

Raman

Ratnam

et al. 2016

Radio Science

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A comprehensive study on diurnal variation of ducting using high vertical and temporal resolution radiosonde measurements over the Indian tropical region, Gadanki (13.5°N, 79.2°E), was presented. The diurnal variation of ducts was examined statistically based on both the refractivity and modified refractivity using 3-hourly radiosonde soundings obtained during October 2010 to March 2014 as a part of tropical tropopause dynamics (TTD) campaigns conducted under Climate and Weather of Sun Earth System (CAWSES) India Phase II program. Strong diurnal variation in the altitude of occurrence of the duct has been found and is at maximum altitude (~2.5 km) during 11-17 LT. Interestingly, it is found that the occurrence of duct altitude closely follows the boundary layer altitude. Diurnal variation of duct altitude is maximum during postmonsoon followed by winter, monsoon, and minimum in premonsoon. However, duct strength is maximum during winter followed by premonsoon, postmonsoon, and minimum in monsoon. Duct thickness is found to be varying between 0.4 km and 1 km diurnally with the highest thickness during the winter season. Strong diurnal and seasonal variation in the percentage occurrence of the ducts was found with the highest percentage of ducts observed during winter (77%) followed by postmonsoon (51%), premonsoon (44%), and monsoon (10%). All the characteristics of ducts during all the seasons are maximum at 14 LT due to the high solar irradiance over Gadanki from 11 to 17 LT. The minimum frequency being trapped has been investigated and found that wave trapping occurs for the radars with frequencies 56-438 MHz over this station.

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Effect of the annular solar eclipse of 15 January 2010 on the lower atmospheric boundary layer over a tropical rural station

Cited by 30 publications

References 23 publications

The changes in near‐surface ozone and precursors at two nearby tropical sites during annular solar eclipse of 15 January 2010

The changes in near‐surface ozone and precursors at two nearby tropical sites during annular solar eclipse of 15 January 2010

Effects of the 20 March 2015 solar eclipse in Strasbourg, France

Diurnal variation of ducts observed over a tropical station, Gadanki, using high‐resolution GPS radiosonde observations

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