| 21 Jul 2025
Variability and trend analysis of temperature in the upper troposphere and stratosphere region over the tropics (Réunion), by combining balloon-sonde and satellite measurements
Abstract. Tropopause height and temperature play a crucial role in atmospheric chemistry and radiative forcing and serve as key indicators of anthropogenic climate change. However, accurately determining this parameter requires advanced remote sensing techniques. This study compares tropopause height estimates from in-situ and remote sensing instruments (SHADOZ and COSMIC-1) with reanalysis data from MERRA-2 over Réunion from 2006 to 2020. The results reveal strong agreement between vertical temperature profiles obtained from SHADOZ and COSMIC-1, demonstrating that both can reliably estimate tropopause height using the Cold Point Temperature (CPT) and/or Lapse Rate Temperature (LRT) methods. Conversely, while MERRA-2 assimilates data from these sources, its fixed vertical resolution limits its ability to capture tropopause height variations accurately. Given the consistency between SHADOZ and COSMIC-1, their data were combined to construct a more refined dataset, which was then used to assess temperature trends. The analysis indicates a high influence of annual and semi-annual oscillations in Tropopause height dynamics, as well as, a decreasing trend in CPT and a slight increase in the Lapse Rate Tropopause (LRT) height.
Reviewer´s comments on Manuscript 10.5194/egusphere-2025-3398
Variability and trend analysis of temperature in the Upper troposphere and stratosphere region over the tropics (Réunion), by combining balloon-sonde and satellite measurements
by
Gregori de Arruda Moreira, Hassan Bencherif, Tristan Millet, Damaris Kirsch Pinheiro
The present manuscript deals with temperature and tropopause height measured over a tropical site, Réunion (21.10° S; 55.48° E), an island in Indic Ocean from 2006 to 2020. Three types of measurements are used to provide data: local balloon-borne temperature profiles (SHADOZ), satellite by using GNSS-RO technique at COSMIC-1, and reanalysis data from MERRA-2. Tropopause heights are obtained using the Cold Point Temperature (CPT) and/or Lapse Rate Temperature (LRT) methods. Those measurements are compared and show a good consistency, mainly from 10 to 30 km height between SHADOZ and COSMIC-1. So, their data was combined for constructing a more refined dataset, which was then used to fit a model which considers the AO, SAO, QBO, ENSO, SSN and IOD, as the linear trend. As expected, the analysis indicated a main influence of AO and SAO oscillations in Tropopause height dynamics, as well as a decreasing trend in CPT and a slight increase in the Lapse Rate Tropopause (LRT) height. The paper is well written and well-structured, the methodology seems to be correct, and the subject has merits and is of interest for Annales Geophysicae. However, this reviewer has concerns about some points that should be addressed by the authors before an acceptance recommendation. The authors should provide a complete revision of the references as indicated below. Therefore, as the subject of the paper is very interesting, I am ready to recommend this manuscript for publication after taken into consideration the above points and after giving a detailed response to my comments.
Minor comments:
- Line 31: “Niño” not “Ninõ”
- Line 334: Fig. 10 is Fig. 9 and the plots should contain a) and b).
Also, in relation to Figure 9 what are the meaning of the two slopes inside the gray rectangles?
Additionally, do the slopes lines have deviation increasing with time? Justify or correct.
References:
There are many inconsistencies in the references with works cited but not listed and listed and not cited. Although this is not a reviewer’s duty I have patiently indicated to the authors the required changes as follows.
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11.
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