Perceptible Water Vapor Research Articles

Variations in GPS precipitable water vapor and rainfall during the 2006–2019 Mei-yu season in Taiwan

The Mei-yu season contributes 26.3% of the annual precipitation and provides important water resources to Taiwan. GPS meteorology derives continuous, real-time and high spatial coverage of perceptible water vapor (PWV), which supports weather forecasting for rainfall indicators. This study analyzes the long-term spatial–temporal changes in GPS PWV and rainfall data during the Mei-yu season from 2006 to 2019. The daily average data show that the Mei-yu season extended in recent years. Both daily rainfall and PWV increase in mid-May and rainfall reaches a maximum in early June, while PWV maintains stable in June. The yearly results show that the trend of the accumulated rainfall in the Mei-yu season is flat, and that PWV increases by 13% over 14 years, which may be due to global warming as the trend of temperature increases by 8%. Spatially, PWV is significantly higher in southern Taiwan during the Mei-yu season, and rainfall increased the most in both the central and southern mountain regions.

Astronomy from Dome A in Antarctica

Dome A in Antarctica has been demonstrated to be the best site on earth for optical, infrared, and terahertz astronomical observations by more and more evidence, such as excellent free-atmosphere seeing, extremely low perceptible water vapor, low sky background, and continuous dark time, etc. In this paper, we present a complete picture of the development of astronomy at Dome A from the very beginning, review recent progress in time-domain astronomy, demonstrate exciting results of the site testing, and address the challenges in instrumentation. Currently proposed projects are briefly discussed.

Sea Fog Analysis Using Jeju Island GNSS Observables to Prevent Marine Accidents

Ha, J.; Lee, J.K., and Park, S. J., 2019. Sea fog analysis using Jeju Island GNSS observables to prevent marine accidents. In: Lee, J.L.; Yoon, J.-S.; Cho, W.C.; Muin, M., and Lee, J. (eds.), The 3rd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 91, pp. 346-350. Coconut Creek (Florida), ISSN 0749-0208.Sea fog leads to poor visibility for ship navigation, and thus is a major cause of severe marine accidents such as groundings and collisions between ships and unmapped objects such as icebergs. In this study, a temporary GNSS observatory was installed at the Gosan weather station on Jeju Island, the largest island in South Korea and located along its busiest shipping lanes, to determine the feasibility of using GNSS measurements to observe fog. In Korea, the greatest amount of sea fog occurs between April and September. In the South Sea where Jeju Island is located, the heaviest fog occurs around July and August. Accordingly, from the 11th to the 14th of August 2009, the temporary GNSS observatory was used to collect data describing the perceptible water vapor and an automatic weather station was used to measure the mixing ratio in the area of Jeju Island. When analyzed and compared to radiosonde and other meteorological data, this data indicated that the GNSS-measured perceptible water tended to increase prior to the occurrence of precipitation and fog, while conversely the AWS-measured mixing ratio tended to decrease. When fog occurred prior to rain, the GNSS-measured perceptible water decreased, demonstrating that it reacts sensitively to the occurrence of fog. It was also found that the increasing trend of the AWS-measured mixing ratio was somewhat delayed prior to the occurrence fog, indicating a close relationship between the two.

Design of a near-infrared sky brightness monitor and field measurement at the Ngari Observatory, Tibet

The Ngari (Ali) observatory is located in Ngari, Tibet, a region known as “the roof of the roof of the world.” The observatory benefits from abundant photometric nights, low perceptible water vapor, high transmittance, and good seeing. Due to these advantages, it promises to be one of the best locations in the world at which to make infrared and submillimeter observations. However, no data on the sky background radiation at this location are available, impacting the planning of future facilities at the observatory. To remedy this deficiency, a near-infrared sky brightness monitor (NISBM) has been designed to obtain data in the J, H, and Ks bands. This monitor is based on an InGaAs photoelectric diode and uses chopper modulation and digital lock-in amplifier processing, which considerably enhance its signal-to-noise ratio, detectivity, and data acquisition speed. An independent device has been designed for each band (J, H, and Ks) and calibrated in the laboratory. The NISBM was installed at the Ngari observatory in July 2017 and has obtained the first NIR sky brightness data for that location.

Calculation of Greenland and Antarctica Glaciers' Weights Causing Some Earthquakes and Volcanic Activities

Global warming is very important subject for environmental physics. Although the earth seems like inanimate, it acts just like a live mechanism which is called as Glacial-Interglacial Ice. One can consider that there are three periods for this forming, say major (100,000 years), minor (12,000 years) and smaller (1000 years) ice ages. The temperature of the earth is a ected by increasing especially CO2 and other sera gases in the atmosphere. The solar radiation re ected from the earth surface cannot go back to the space due to the sera gases and is absorbed by the atmosphere. After the industrial revolution at the beginning of 20th century, especially in the last 30 years, the amount of CO2 and the other carbon gases emitted into the atmosphere has been increasing and causing natural disasters like irregular local temperature changes, oods, melting glaciers, and more powerful hurricanes. The solar radiations are mostly re ected by glaciers which are signi cant formations on the earth. Melting of these glaciers reduces the surface re ection and causes more absorption of solar radiation by the earth. In addition, sea level, amount of fresh water, and perceptible water vapor in the atmosphere may increase. In this study, Greenland and Antarctica glaciers' weights which press the plates downward are calculated. Melting the glaciers, the plates get rid of the pressure and rise upward over the mantle, and may cause some earthquakes, and volcanic activities such as Thoku earthquake in Japan and Eyjafjallajokull and Grimsvotn volcanos in Iceland.

Identifying the Relationship between GPS Data Quality and Positioning Precision: Case Study on IGS Tracking Stations

AbstractThe number of global positioning system (GPS) tracking stations is increasing, primarily because the stations are multifunctional. In civil engineering, they can be used for precision positioning; in the earth sciences, they can be used to monitor faults and earthquakes; and in the atmospheric sciences, they can be applied to predict perceptible water vapor. Currently, there are more than 400 GPS stations in Taiwan; however, the data obtained through such stations are not being assessed carefully. Experienced scientists and engineers examine the data in advance to see if they qualify for research purposes, but inexperienced users can adopt poor quality data that eventually lead to inaccurate research results. Of the observation stations with receivers that were renewed between 2006 and 2008 in the International GNSS Service Network, four stations (ZIMM, BOR1, NRC1, and NICO) were selected to be the subjects of this research. Six indexes of data quality were observed to calculate the quality of dat...

Thermal infrared instruments from Antarctica: what can be gained

The gain of thermal infrared instruments in the 2–25 μ m wavelength range from Antarctica is summarized by comparing three parameters: the ambient temperature; the atmospheric transparency, with perceptible water vapor content (PWV) in particular; and the image quality. For the 2 m class infrared telescope projects at Dome C the estimated mid infrared point source sensitivity can be compared to the sensitivities reached at 10 m class telescopes elsewhere. This comparison favors a thermal IR instrument at Dome C with focus on key science cases; two examples are: i) Survey type projects, such as mid infrared photometric imaging or spectro–polarization campaigns of YSO. Or ii) monitoring and rapid response observations on the Galactic Centre, the LMC, SN or GRB.

Parameterization of a simple model to estimate monthly global solar radiation based on meteorological variables, and evaluation of existing solar radiation models for Tabouk, Saudi Arabia

Using 9 years of solar radiation data, we established a simple model to calculate the monthly mean global solar radiation on a horizontal surface in Tabouk (28.38° N, 36.6° E, Saudi Arabia). The model correlates the global solar radiation with five meteorological parameters. These parameters are the perceptible water vapor, air temperature, relative humidity, atmospheric pressure, and the mean monthly daily fraction of possible sunshine hours. The estimated global radiation from the model was compared with the measured values using the mean bias error (MBE), coefficient of correlation ( R), root mean square error (RMSE), and mean percentage error (MPE). The t statistics were also applied as another indication of suitability. The model has a high coefficient of correlation ( R = 0.99), MBE = −14 × 10 −4 kW h/m 2, RMSE = 0.10 kW h/m 2, and MPE = −0.03%. It is believed that the model developed in this work is applicable for estimating, with great accuracy. The monthly mean daily global radiation at any site having similar conditions to those found in Tabouk. Furthermore, 29 regression models available in the literature were used to estimate the global solar radiation data for Tabouk. The selected models were different in terms of the variables they use and in the number of the variables they contained. The models were compared on the basis of the statistical errors considered above. Apart from Abdall’s model, which showed a reasonable estimate (MPE = −2.04%, MBE = −0.22 kW h/m 2, and RMSE = 0.59 kW h/m 2), all the models under or overestimate the measured solar radiation values. Comparisons between these models and the produced model, from this study, were also considered. According to the statistical results, the model of Abdall showed the prediction closest to those estimated using the developed model.