Data Descriptor: Daily observations of stable isotope ratios of rainfall in the tropics

Abstract

We present precipitation isotope data (δ2H and δ18O values) from 19 stations across the tropics collected from 2012 to 2017 under the Coordinated Research Project F31004 sponsored by the International Atomic Energy Agency. Rainfall samples were collected daily and analysed for stable isotopic ratios of oxygen and hydrogen by participating laboratories following a common analytical framework. We also calculated daily mean stratiform rainfall area fractions around each station over an area of 5° x 5° longitude/latitude based on TRMM/GPM satellite data. Isotope time series, along with information on rainfall amount and stratiform/convective proportions provide a valuable tool for rainfall characterisation and to improve the ability of isotope-enabled Global Circulation Models to predict variability and availability of inputs to fresh water resources across the tropics.

Unique Post-telemetry Recapture Enables Development of Multi-Element Isoscapes From Barnacle Shell for Retracing Host Movement

“…Our linear equation for NW Australia aligned well with these expectations, returning a gradient of 0.81 /PSU, which is steeper than both the global tropical (0.25 /PSU) and NW Atlantic extra-tropical (0.57 /PSU) slopes provided by Schmidt et al (2007). The intercept of −28.2 is lower than expected, given that this reflects the freshwater "end-member" rainfall δ 18 O value in the region, which is generally in the range of −5 to 15 (e.g., Hughes and Crawford, 2012;Munksgaard et al, 2019). The exact cause of this difference is unknown, but it could be due, in part, to highly seasonal evaporative processes (as suggested by Schmidt et al, 2007), related to the role that this subtropical region plays in exporting water vapor to the extra-tropics.…”

Statistical Analysis of the Precipitation Isotope Data with Reference to the Indian Subcontinent

“…Precipitation isotopic data on a daily scale has been collected from several locations in India. These sites are Port Blair in the Andaman Islands (data available: 2012-2018; [26,[28][29][30]), Minicoy Island in the Arabian Sea (2015-2018; [31]); Kolkata in east India (2015-2018; [26]); Darjeeling (2013-2018) and Tezpur in northeast India (2016-2018; [26]); Ahmedabad (2007) [25] and Pune in west India (2014-2018; [32,33]), Bandipora in north India (July-2016 to June-2018; [34]) and Kozhikode in south India [22]. Precipitation isotope data of a few sites in Bangladesh have also been used [29,35].…”

“…Additionally, precipitation isotope data across the tropics have also been used to examine the statistical behavior of the isotopic data on a global scale. The data is available in [29].…”

“…In this context, it is to be noted that the precipitation isotope data were obtained from nineteen sites across the tropics, including an extra-tropical area Nagoya, in Japan. Description of the sites and data are available in [29]. When the K value of d-excess was calculated for the entire dataset, an unusually high value (117) was obtained.…”

What Causes the Postmonsoon 18O Depletion Over Bay of Bengal Head and Beyond?

“…Daily data from two stations over the southeast TP at Lulang and Nuxia (Yang et al, 2017) as well as a merged daily δ 18 O time series from Wengguo, Baidi, and Dui stations in the Yamdruk-tso basin (Wang et al, 2020) were used in this study. In addition, the International Atomic Energy Agency Coordinated Research Project F31004 has recently released daily precipitation isotope data from 19 stations across the tropics (Munksgaard et al, 2019). The daily data at Barisal, Bangladesh from 2013 to 2015 within this dataset will be a major focus of this study.…”