Seasonal and interannual variations of water vapor in the upper troposphere and lower stratosphere over the Asian Summer Monsoon region- in perspective of the tropopause and ocean-atmosphere interactions

Das, Siddarth Shankar; Suneeth, K. V.

doi:10.1016/j.jastp.2020.105244

Cited by 12 publications

(13 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Avery et al. (2017) and Das and Suneeth (2020) have shown a large anomaly in lower SWV during the 2015–2016 strong El Niño event, which is abnormal. They found that convective moistening of the lower stratosphere also affects the entry value of the SWV.…”

Section: Introductionmentioning

confidence: 96%

“…Diallo et al (2019) determined the relative contributions of planetary and gravity wave drags to changes in the BD circulation. Avery et al (2017) and Das and Suneeth (2020) have shown a large anomaly in lower SWV during the 2015-2016 strong El Niño event, which is abnormal. They found that convective moistening of the lower stratosphere also affects the entry value of the SWV.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Impacts of the Indo‐Pacific Warm Pool on Lower Stratospheric Water Vapor: Seasonality and Hemispheric Contrasts

Zhou

Chen

et al. 2021

JGR Atmospheres

View full text Add to dashboard Cite

Global mean surface temperature warmed by about 0.12°C per decade from the 1950s to 2000 most likely in response to significant increases in anthropogenic carbon dioxide and other greenhouse gases (IPCC, 2013). As an important greenhouse gas (GHG), stratospheric water vapor (SWV) contributes substantially to global climate change by altering the infrared opacity of the atmosphere (e.g., Soden & Held, 2006), providing strong positive feedback to global warming at +0.3 W/(m 2 •K) (Dessler et al., 2013). Sensitivity studies of climate models have demonstrated that even a small increase in the lower SWV can lead to marked changes in radiative forcing, resulting in cooling of the lower stratosphere (

show abstract

Section: Introductionmentioning

confidence: 96%

mentioning

confidence: 99%

Impacts of the Indo‐Pacific Warm Pool on Lower Stratospheric Water Vapor: Seasonality and Hemispheric Contrasts

Zhou

Chen

et al. 2021

JGR Atmospheres

View full text Add to dashboard Cite

show abstract

“…It is well known that most of the WV enters the stratosphere through the tropical tropopause (Fueglistaler et al, 2009), and the temperature present at the tropical tropopause strongly controls the WV entering the lower stratosphere (LS). It is also well documented that several processes such as convection, the strength of the Brewer-Dobson circulation, El Niño-Southern Oscillation (ENSO), and quasi-biennial oscillation (QBO) are responsible for the WV transport to the UTLS region (Holton et al, 1995;Dessler et al, 2014;Jiang et al, 2015). Other factors such as gravity waves and horizontal advection can also influence the WV transport in the UTLS region.…”

Section: Introductionmentioning

confidence: 99%

Structure, dynamics, and trace gas variability within the Asian summer monsoon anticyclone in the extreme El Niño of 2015–2016

et al. 2021

View full text Add to dashboard Cite

Abstract. A weak El Niño during 2014–2015 boreal winter developed as a strong boreal summer event in 2015 which continued and even enhanced during the following winter. In this work, the detailed changes in the structure, dynamics, and trace gases within the Asian summer monsoon anticyclone (ASMA) during the extreme El Niño of 2015–2016 is delineated by using Aura Microwave Limb Sounder (MLS) measurements, COSMIC radio occultation (RO) temperature, and National Centers for Environmental Prediction (NCEP) reanalysis products. Our analysis concentrates only on the summer months of July and August 2015 when the Niño 3.4 index started to exceed values of 1.5. The results show that the ASMA structure was quite different in summer 2015 as compared to the long-term (2005–2014) mean. In July, the spatial extension of the ASMA is greater than the long-term mean in all the regions except over northeastern Asia, where it exhibits a strong southward shift in its position. The ASMA splits into two, and the western Pacific mode is evident in August. Interestingly, the subtropical westerly jet (STJ) shifted southward from its normal position over northeastern Asia, and as a result midlatitude air moved southward in 2015. Intense Rossby wave breaking events along with STJ are also found in July 2015. Due to these dynamical changes in the ASMA, pronounced changes in the ASMA tracers are noticed in 2015 compared to the long-term mean. A 30 % (20 %) decrease in carbon monoxide (water vapor) at 100 hPa is observed in July over most of the ASMA region, whereas in August the drop is strongly concentrated at the edges of the ASMA. A prominent increase in O3 (> 40 %) at 100 hPa is clearly evident within the ASMA in July, whereas in August the increase is strongly located (even at 121 hPa) over the western edges of the ASMA. Further, the temperature around the tropopause shows significant positive anomalies (∼ 5 K) within the ASMA in 2015. The present results clearly reveal the El-Niño-induced dynamical changes caused significant changes in the trace gases within the ASMA in summer 2015.

show abstract

“…The maximum amount of WV and other pollutants are injected into the stratosphere over the ASM region (Fu et al 2006). Earlier studies have shown that the maximum amount of WV is accumulated in the UTLS over the ASM anticyclone (Tibetan Plateau) during boreal summer (Randel and Park, 2006;Das and Suneeth 2020). Nützel et al (2019) found that ASM contributes 14 % of SWV in tropics using a chemistry-transport model.…”

Section: Introductionmentioning

confidence: 99%

“…It is observed that stronger convection leads to a relatively dry stratosphere, whereas weaker convection leads to a wetter stratosphere (Randel et al 2015). In addition to these processes, Quasi-Biennial Oscillation (QBO) also controls the entry of WV to the lower stratosphere (Dessler et al 2014;Das and Suneeth, 2020). Once the WV enters the lower stratosphere, it further propagates both vertically and quasi-horizontally (Rosenlof et al 1997).…”

Section: Introductionmentioning

confidence: 99%

Diurnal Variability of Lower and Middle Atmospheric Water Vapour Over The Asian Summer Monsoon Region: First Results From COSMIC-1 and TIMED-SABER Measurements

Das

Uma²,

Suneeth

2021

Preprint

Self Cite

View full text Add to dashboard Cite

First observations on the vertical structure of diurnal variability of tropospheric water vapour in the lower and middle atmosphere using 13 years of COSMIC and 18 years of SABER observations are presented in this paper. The most significant and new observation is that the middle stratospheric water vapour (SWV) enhancement is observed between 9-18 LT, whereas it is between 6-15 LT near tropopause in all the seasons. The diurnal amplitude of water vapour near tropopause is between 0.3-0.4 ppmv. Bimodal peaks are found in the diurnal amplitude of SWV, maximizing between 25-30 km (~0.4 ppmv) and 45-50 km (~0.6 ppmv). The analysis reveals that the diurnal variability in the lower SWV is controlled by the tropical tropopause temperature, whereas the middle and upper SWV is controlled by methane oxidation. The results are presented and discussed in the light of present understanding.

show abstract

Seasonal and interannual variations of water vapor in the upper troposphere and lower stratosphere over the Asian Summer Monsoon region- in perspective of the tropopause and ocean-atmosphere interactions

Cited by 12 publications

References 50 publications

Impacts of the Indo‐Pacific Warm Pool on Lower Stratospheric Water Vapor: Seasonality and Hemispheric Contrasts

Impacts of the Indo‐Pacific Warm Pool on Lower Stratospheric Water Vapor: Seasonality and Hemispheric Contrasts

Structure, dynamics, and trace gas variability within the Asian summer monsoon anticyclone in the extreme El Niño of 2015–2016

Diurnal Variability of Lower and Middle Atmospheric Water Vapour Over The Asian Summer Monsoon Region: First Results From COSMIC-1 and TIMED-SABER Measurements

Contact Info

Product

Resources

About