出版者

National Institute of Polar Research

雑誌

Polar Data Journal (ISSN:24326771)

巻号頁・発行日

vol.5, pp.89-98, 2021-09

---

Reconstructions of the past variations of atmospheric composition are important for better understanding of the changes in climate and atmospheric chemistry. The data from direct atmospheric observations of various trace gas mole fractions and isotope ratios have become available over the last few decades. The analyses of air bubbles in polar ice cores have provided those from the pre-industrial era to the mid-20th century. Old air is also found in porous snow layers (firn) on top of polar ice sheets, because the gas movements in firn occur mainly by molecular diffusion. Depth profiles of firn air components are therefore useful for bridging the records from direct observations and ice-core analyses (covering up to about a century). The firn air data are also helpful for constraining firn air transport models toward better understanding of snow densification and interpretation of ice core data. Here we present the depth profiles of air composition in the firn at the North Greenland Ice Core Project (NGRIP) site. Various gas components, including atmospheric O2/N2 ratio, greenhouse gases, halocarbons and their isotope ratios, were measured from air samples collected from the NGRIP firn by using combination of high-precision measurement systems. The data are presented in a spreadsheet format (.xlsx).

出版者

National Institute of Polar Research

雑誌

Polar Data Journal (ISSN:24326771)

巻号頁・発行日

vol.1, pp.1-16, 2017-10

---

Kinematic GPS measurements provide in-situ data crucial for measuring the surface elevation change of glaciers. Owing to their accuracy, which is generally better than half meter, surface elevations derived from kinematic GPS surveys are useful and essential for generating precise digital elevation models (DEMs) and evaluating geometry changes of glaciers. We present a surface elevation data set derived from kinematic GPS measurements covering the lower 5 km of Qaanaaq and Bowdoin Glaciers in northwestern Greenland. The data includes elevations over ice-free terrain nearby the glaciers, important for calibrating remote sensing data. More than 600,000 GPS survey data points were processed to produce a 1-m resolution mesh grid of elevation data in a CSV file format. Based on our error analysis, the accuracies of the elevation data are better than 0.2 and 0.3 m in horizontal and vertical directions, respectively. This dataset can be utilized to investigate glacier surface elevation changes by making comparison with DEMs obtained in the past, and from future remote sensing and in-situ observations.

出版者

National Institute of Polar Research

雑誌

Polar Data Journal (ISSN:24326771)

巻号頁・発行日

vol.4, pp.55-60, 2020-04

---

Twice daily upper atmospheric sounding observation was conducted at research station Ice Base Cape Baranova during the Year Of Polar Prediction (YOPP) Special Observing Periods (SOPs) of 2018 as a part of Polar Prediction Project (PPP) . This station is noteworthy as it is one of the representative observation stations within the Arctic Sea. During the two SOPs, a total of 286 soundings were made (113 in late winter and 173 in summer). Data is formatted into a NOAA NCEI compliant NetCDF format in accordance to the YOPP data portal guidelines.