Scientists fear major volcanic eruption in the Philippines

Investigation of weather anomalies in the low-latitude islands of the Indian Ocean in 1991

Annales Geophysicae ◽

10.5194/angeo-33-789-2015 ◽

2015 ◽

Vol 33 (7) ◽

pp. 789-804 ◽

Cited By ~ 1

Author(s):

A. Réchou ◽

S. Kirkwood

Keyword(s):

Indian Ocean ◽

El Niño ◽

Volcanic Eruption ◽

El Nino ◽

Sunshine Duration ◽

Global Precipitation Climatology Project ◽

The Philippines ◽

Quasi Biennial Oscillation ◽

Mount Pinatubo ◽

The Indian Ocean

Abstract. Temperature, precipitation and sunshine duration measurements at meteorological stations across the southern Indian Ocean have been analysed to try to differentiate the possible influence of the Mount Pinatubo volcanic eruption in the Philippines in June 1991 and the normal weather forcings. During December 1991, precipitation on the tropical islands Glorieuses (11.6° S) and Mayotte (12.8° S) was 4 and 3 times greater, respectively, than the climatological mean (precipitation is greater by more than than twice the standard deviation (SD)). Mean sunshine duration (expressed in sun hours per day) was only 6 h on Mayotte, although the sunshine duration is usually more than 7.5 ± 0.75 h, and on the Glorieuses it was only 5 h, although it is usually 8.5 ± 1 h. Mean and SD of sunshine duration are based on December (1964–2001 for Mayotte, 1966–1999 for the Glorieuses). The Madden–Julian Oscillation (MJO) is shown to correlate best with precipitation in this area. Variability controlling the warm zone on these two islands can be increased by the Indian Ocean Dipole (IOD), El Niño, the quasi-biennial oscillation (QBO) and/or solar activity (sunspot number, SSN). However, temperature records of these two islands show weak dependence on such forcings (temperatures are close to the climatological mean for December). This suggests that such weather forcings have an indirect effect on the precipitation. December 1991 was associated with unusually low values of the MJO index, which favours high rainfall, as well as with El Niño, eastern QBO and high SSN, which favour high variability. It is therefore not clear whether the Mount Pinatubo volcanic eruption had an effect. Since the precipitation anomalies at the Glorieuses and Mayotte are more or less local (Global Precipitation Climatology Project (GPCP) data) and the effect of the Pinatubo volcanic cloud should be more widespread, it seems unlikely that Pinatubo was the cause. Islands at higher southern latitudes (south of Tromelin at 15.5° S) were not affected by the Pinatubo eruption in terms of sunshine duration, precipitation or temperature.

Download Full-text

Measurement report: Immediate impact of the Taal volcanic eruption on atmospheric temperature observed from COSMIC-2 RO measurements

10.5194/acp-2020-513 ◽

2020 ◽

Author(s):

Saginela Ravindra Babu ◽

Yuei-An Liou

Keyword(s):

Relative Humidity ◽

Volcanic Eruption ◽

Temperature Inversion ◽

Atmospheric Temperature ◽

The Philippines ◽

Strong Increase ◽

Temperature Structure ◽

Temperature Profiles ◽

Taal Volcano ◽

Strong Winds

Abstract. For the first time after 43 years of its previous eruption in 1977, the Taal volcano in the Philippines (14° N, 120.59° E) erupted in the afternoon of 12 January, 2020. Interestingly, the Taal volcanic eruption was associated with a strong anticyclonic circulation at the upper levels over the western Pacific region in the northern hemisphere. As a result, the volcanic plumes were carried through the background upper level strong winds to the anticyclone over the Pacific Ocean within a few days following the eruption. In this study, the detailed vertical structure and the day-to-day temperature variability in response to the eruption is delineated by using high-resolution temperature measurements from the recently launched Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC)-2 radio occultation (RO) data. We describe the vertical temperature structure near (within 2 degree radius) and away (~ 5 degree radius) from the volcano during its intense eruption day (13 January 2020). A significant temperature inversion at ~ 15 km altitude is observed in the nearest temperature profiles (within 2 degree radius). Multiple tropopauses are evident in the temperature profiles that are available away from the volcano (~ 5 degree radius). The cloud top altitude of 15.2 km detected from the RO bending angle anomaly method is demonstrated. Furthermore, the diurnal temperature and relative humidity anomalies are estimated over ± 5° latitude and longitude radius from the volcano center and over the region of 10–20° N, 160–180° E with respect to the mean temperature of one week before the eruption. A persistent warming layer is observed at 16–19 km altitude range in both regions for several days after the eruption. A strong increase of ~ 50 % relative humidity at 15 km altitude is also noticed just after the eruption in the Taal volcano region. The present work shows the advantages and usefulness of the newly-launched COSMIC-2 data for near real-time temperature monitoring at shorter time scales with sufficient data.

Download Full-text