An insight into the western Pacific wintertime moisture sources using dual water vapor isotopes
Journal
Journal of Hydrology
Journal Volume
547
Pages
111-123
Date Issued
2017
Author(s)
Abstract
Continuous measurements of isotopic ratios in atmospheric water vapor in a western Pacific region (Taipei, Taiwan) in two winters (2011 and 2012) were made and analyzed to understand the moisture source characteristics. In wintertime, the so-called East Asian Monsoon dominates, largely affecting the climate and meteorology of this region. Being located in the subtropical region, Taipei provides an ideal opportunity for studying interactions between high latitude cold and dry continental air masses and low to mid-latitude warm and wet oceanic air. Indeed, the dual isotope function, d-excess shows the presence of two distinct moisture sources, contributing to the winter vapor isotope variability. Undoubtedly, the dominant moisture source is the high latitude continental cold air masses reaching Taipei with d-excess values of >20‰. Alongside, wet and warm air masses characterized by strong air-sea interaction from the surrounding oceans, possessing d-excess value of ∼10‰ also play a role. The interactions of these two distinct air masses cause the d-excess values to change by as much as ∼20‰ in a few days. Multiple regression analysis shows that source moisture composition and water vapor mixing ratio combined control over 60% of the observed variability. We developed a box model to show that both high and low d-excess events in the winter are primarily controlled by the humidity deficit over the ocean. The information obtained in this study could be used in interpreting the paleoclimate proxies within the East Asian region. © 2017 Elsevier B.V.
Subjects
Box model; d-excess; Humidity deficit; Source moisture; Water vapor
SDGs
Other Subjects
Atmospheric humidity; Humidity control; Isotopes; Moisture; Regression analysis; Air sea interactions; Atmospheric water vapor; Box models; Continental air mass; Continuous measurements; Moisture composition; Multiple regression analysis; Water vapor mixing ratio; Water vapor; air mass; air-sea interaction; atmospheric moisture; cold air; humidity; isotopic ratio; mixing ratio; monsoon; numerical model; subtropical region; water vapor; winter; Pacific Ocean; Pacific Ocean (West); Taipei; Taiwan
Type
journal article