Tenki, Vol. 64, No. 1

(Tenki is the bulletin journal of the Meteorological Society of Japan in Japanese.)

TENKI, Vol. 64, No. 1, pp. 5-17, 2017

Estimates of Wet Scavenging Coefficients of Atmospheric Contaminants

Keizo NAKAMURA* and Masashi MITANI**

* Faculty of International Studies, Keiai University, Anagawa 1-5-21, Inage-ku, Chiba, 263-8588, Japan.
** Hiraoka 9-1-14-1, Kiyota-ku, Sapporo, 004-0879, Japan.

(Received 24 April 2015; Accepted 31 August 2016)


The wet scavenging coefficients of atmospheric contaminants, nss -SO42-, NO3-, NH4+, Na+ and nss-Ca2+, are estimated from the temporal variations of the contaminant concentration of the precipitations observed for twelve years from 1997 at Sakura, Chiba Prefecture, Japan. These scavenging coefficients were obtained with respect to the cumulative amount of precipitation so that the scavenging coefficients λ have the unit of mm-1. λ is observed to be independent of precipitation intensity P right after the onset of the precipitation. Investigating the scavenging coefficients Λ(s-1) estimated from λ and P, it is found that Λ for each component are of the order of 10-5 to 10-2 s-1 under P of 0.1 to 50mm · h-1.
Although Λ is expressed in first-order expression of P for each contaminant without respect to the seasons, the expression is explicitly affected by cloud types. The relation between Λ and P is interpreted with a simple model of the scavenging process.

Tenki, Vol. 64, No. 1

(Tenki is the bulletin journal of the Meteorological Society of Japan in Japanese.)

TENKI, Vol. 64, No. 1, pp. 19-36, 2017

Analysis of Atmospheric Environments for Convective Cloud
Development around the Central Mountains in Japan during Warm
Seasons Using Ground-Based Microwave Radiometer Data

Kentaro ARAKI*1, Masataka MURAKAMI*2, Teruyuki KATO*3 and Takuya TAJIRI*3

*1 (Corresponding author) Meteorological Research Institute, Japan Meteorological Agency. E-mail: araki@mri-jma.go.jp
*2 Institute for Space-Earth Environmental Research, Nagoya University/Meteorological Research Institute, Japan Meteorological Agency.
*3 Meteorological Research Institute, Japan Meteorological Agency.

(Received 26 November 2015; Accepted 12 September 2016)


Convective clouds often develop in the afternoon on fair-weather summer days around the Central Mountains in Japan. Vertical structure and diurnal variation of the dynamic and thermodynamic environments for the convective cloud development have not been well understood because of sparse observation data. In this study, vertical structure and diurnal variation of the environments for both active and non-active convection cases were statistically investigated using the data from a ground-based microwave radiometer (MWR), surface weather observation system, a wind profiler, and radiosonde during July and August from 2012 to 2014.
Firstly, typical cases were extracted and classified into active and non-active convection cases. From the results of surface and wind profiler observations, it is shown vertical structures and diurnal variations of thermally-induced local circulations were similar for both active and non-active cases. Vertical profiles of atmospheric temperature and water vapor were retrieved by a one-dimensional variational (1DVAR) technique combining the MWR observation data and the results of the JMA Non-Hydrostatic Model (NHM) simulations. Comparison with radiosonde data, surface weather data, and cloud base temperature obtained from an infrared radiometer indicated that 1DVAR-derived profiles were more reliable than NHM-simulated profiles. Statistical analysis based on the 1DVAR-derived thermodynamic profiles revealed that the lifted condensation level (LCL) increased and the level of free convection decreased during daytime for both active and non-active cases, although the NHM could not reproduce the diurnal variation of the LCL. It was found that the diurnal change of unstable atmospheric stratification was caused by increased temperature and water vapor density at the altitudes less than about 1.5km, which was the same vertical scale of thermally-induced local circulation, for both active and non-active cases. Stability indices also showed that atmospheric stratification was significantly unstable for active cases compared with non-active cases.

Tenki, Vol. 64, No. 2

(Tenki is the bulletin journal of the Meteorological Society of Japan in Japanese.)

TENKI, Vol. 64, No. 2, pp. 85-91, 2017

Knowing Forecast Uncertainties to Improve Profits:
A Possibility for Solar Power Businesses

Yoshiyuki TOMIYAMA*

* Weather Environment Education Center, 3-17 Kandanishikicho, Tokyo, Japan.
E-mail: rakufuh@tg.commufa.jp

(Received 4 August 2016; Accepted 6 October 2016)


There may be efforts to know forecast uncertainties, along with to reduce them. Solar power is one of the variable resources, however errors of solar power forecasting are still large. These uncertainties are the risk to solar power businesses, therefore the uncertainty management is a key challenge. This report focused on the characteristics of statistical relation between solar power forecast and actual generation using data normalization method. It demonstrated that the forecast uncertainties known by the method make it possible to improve profits of solar power businesses.

Tenki, Vol. 64, No. 4

(Tenki is the bulletin journal of the Meteorological Society of Japan in Japanese.)

TENKI, Vol. 64, No. 4, pp. 223-233, 2017

Statistical Study of the Effect of Terrain and Land Use Conditions
on Diurnal Pressure Variation.

Shigenori HAGINOYA*

* Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki 305-0052, Japan.
E-mail: shaginoy@mri-jma.go.jp

(Received 12 February 2016; Accepted 31 January 2017)


Harmonic analysis of atmospheric surface pressure was used to investigate the relation between the diurnal component of pressure and the land surface characteristics. The data used for the analysis were annual average pressures observed at meteorological stations in Japan and at some overseas stations. The results indicated that 60-70% of variation in the amplitude and phase of the diurnal component could be explained by using 10 explanatory variables to represent the topographical features and the ground surface conditions within multiple regression analysis. The amplitude and phase corresponded particularly well with the land indicator defined by the land area ratio and the terrain protrusion indicator defined by relief data about the terrain. The amplitude over inland areas where the land indicator increases was larger than over coastal areas. In addition, the amplitude was larger in concave landforms, such as basin and flatland, than in convex landforms, such as mountain peak, depending on the scale of terrain protrusion indicators. The magnitude of amplitude was proportional to the land indicator in flatlands, where protrusion indicators were within -300 to +300 m. The phase did not depend on the terrain protrusion indicator in concave landforms and flatland. In contrast, phase delay of more than 12 h occurred over convex landforms as the protrusion indicator increased. No relation between the phase and the land indicator was found.