著者

Hiroaki Kawase Akihiko Murata Ken Yamada Tosiyuki Nakaegawa Rui Ito Ryo Mizuta Masaya Nosaka Shunichi Watanabe Hidetaka Sasaki

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.2021-001, (Released:2020-12-18)

被引用文献数

12

---

We investigate regional characteristics of future changes in snowfall in Japan under two emission scenarios—RCP2.6 and RCP8.5—using a high-resolution regional climate model with 5 km grid spacing and discuss the influence of changes in atmospheric circulation. The high-resolution model can simulate details of changes in distributions of total snowfall in Japan. Under RCP2.6, the annual total snowfall decreases in most parts of Japan except for Japan's northern island, Hokkaido. In Hokkaido, the winter snowfall increases even under RCP8.5, especially in January and February. The snowfall peak is delayed from early December to late January in Hokkaido. Along the Sea of Japan in eastern Japan, the winter-total snowfall decreases even if the winter mean temperature is below 0°C in the future climate. The different snowfall changes in Hokkaido and on the Sea of Japan side of eastern Japan are caused by precipitation changes in each region. Future changes in atmospheric circulation related to the Aleutian low cause the enhancement and the inhibition of winter precipitation in Hokkaido and the Sea of Japan side of eastern Japan, respectively, contributing to changes in the regional characteristics of snowfall and snow cover in addition to moistening due to atmospheric and ocean warming.

著者

Tetsuya Takemi Takashi Unuma

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.15A-011, (Released:2019-08-26)

被引用文献数

25

---

This study documented the environmental properties of precipitation systems that produced the July 2018 Heavy Rainfall event in Japan. The gridded analysis data were used to diagnose the potential for the development of convective systems in terms of thermodynamic environmental indices. Precipitable water vapor was extremely larger than that seen in the climatology of warm-season quasi-stationary convective clusters (QSCCs). Such an extreme moisture content was realized by very humid conditions at the middle-levels. In contrast, temperature lapse rate in a convectively unstable layer was not so significant in comparison to the QSCC climatology. Among the environmental indices, K Index was shown to describe the potential for the rainfall development. Based on the analysis, the roles of moisture content and profile on the convection development were discussed. It was suggested that the middle-level high humidity contributes to the occurrence of the present heavy rainfall by minimizing negative effects of environmental mixing and by decreasing vertical displacements to reach levels of free convection. In regions where heavy rainfall occurred, an automated algorithm detected the development of QSCCs, which were mostly categorized as a linear type.

著者

Asuka Suzuki-Parker Hiroyuki Kusaka Izuru Takayabu Koji Dairaku Noriko N. Ishizaki Suryun Ham

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.14, pp.97-104, 2018 (Released:2018-07-27)

参考文献数

49

被引用文献数

14

---

Targeting to East Asian summer monsoon for the first time, this study presents an assessment of projection uncertainty in ensemble dynamical downscaling (DDS) simulations. Based on 12-member DDS simulations comprised of three global climate models (GCMs) and four regional climate models (RCMs), we evaluate contributions of GCM and RCM uncertainty to the total uncertainty of summer-time precipitation projections around Japan. Our results show that contribution of RCM uncertainty can be comparable to that of GCM uncertainty in magnitudes. This finding draws a distinction from the past studies showing the dominance of GCM uncertainty. Most notably, our results show that RCM uncertainty for number of precipitating days appears around and over the land. RCM uncertainty for precipitation amounts also shows a dependence on topography but to a lessor degree. These RCM uncertainty characteristics are potentially linked to the difference in various RCM configurations such as physics schemes and model topography. In contrast, GCM uncertainty mostly appears over the ocean, which can be attributed to the difference in the GCM's future projections of East Asian summer monsoon. Our finding may be of an importance for water disaster and water resource management with DDS.

著者

Sho Kawazoe Masaru Inatsu Tomohito J. Yamada Tsuyoshi Hoshino

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.2020-039, (Released:2020-10-28)

被引用文献数

11

---

Synoptic circulation patterns associated with heavy snowfall events in Sapporo are examined using large ensemble simulation with 60-km global climate experiments. For snowfall, a 5-km dynamically downscaled model from the 20-km regional simulation is utilized. To identify synoptic circulation patterns, self-organizing maps (SOMs) are applied, and their response to a warming climate is examined. The authors find that heavy snow events predominantly occur due to low pressure anomalies to the north/east of Hokkaido or over central Japan, and by high pressure anomalies over the Siberian continent. The 4 K warming climate shows robust decreases in heavy snowfall amounts associated with low pressure anomalies over central Japan and increases in heavy snowfall amounts under patterns with high pressure anomalies over Siberia. This is attributed to surface air temperature characteristics in future climates, as precipitation in the former with surface winds transporting warm, moist air from the south and east, develops predominantly above 0°C in the +4 K climate, while the latter, often resulting in intense snow band events, continues to be dominated by temperatures near or below zero.

著者

Masayuki Takigawa Prabir K. Patra Yutaka Matsumi Surendra K. Dhaka Tomoki Nakayama Kazuyo Yamaji Mizuo Kajino Sachiko Hayashida

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.86-91, 2020 (Released:2020-05-27)

参考文献数

39

被引用文献数

3 17

---

The severe air pollution events continue to occur every year during late October and early November in Delhi, forcing air/land traffic disruptions and anxiety in the daily life of the citizens. We analyze the behaviors of the air pollution events in October and November 2019 that arose from the crop-residue burning as seen using remote sensing techniques. Transport pathways and the mean transit time from the fire hotspots are evaluated using the FLEXPART (FLEXible PARTicle dispersion model). Our results suggest that the polluted regions in Delhi are partly influenced by the crop-residue burning. The uncertainty of our evaluation can be attributable to insufficient information on emission sources because the biomass burning emission based on daily-basis fire radiative power (FRP) of Moderate-Resolution Imaging Spectroradiometry (MODIS) is significantly degraded by the existence of hazy clouds. In future, it is desirable to establish a dense measurement network between Punjab and Delhi for the early detection of the source signals of aerosol emissions and their transport in this region. The FLEXPART model simulation shows the transport of emission signals from Punjab to Delhi, which further expands toward the Bengal region within a span of two days.

著者

Takuto Sato Hiroyuki Kusaka Hideitsu Hino

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.104-108, 2020 (Released:2020-06-26)

参考文献数

19

被引用文献数

10

---

This study reveals the best combination of meteorological variables for the prediction of the number of emergency transport due to heat stroke over 64 years old in Tokyo metropolis based on a generalized linear model using 2008-2016 data. Temperature, relative humidity, wind speed, and solar radiation were used as candidates of the explanatory variables. The variable selection with Akaike's information criterion (AIC) showed that all the four meteorological elements were selected for the prediction model. Additional analysis showed that the combination of daily mean temperature, maximum relative humidity, maximum wind speed, and total solar radiation as explanatory variables gives the best prediction, with approximately 19% less error than the conventional single-variable model which only uses the daily mean temperature. Finally, we quantitatively estimated the relative contribution of each variable to the prediction of the daily number of heat stroke patients using standardized partial regression coefficients. The result reveals that temperature is the largest contributor. Solar radiation is second, with approximately 20% of the temperature effect. Relative humidity and wind speed make relatively small contributions, each contributing approximately 10% and 9% of the temperature, respectively. This result provides helpful information to propose more sophisticated thermal indices to predict heat stroke risk.

著者

Haruka Okui Kaoru Sato

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.64-69, 2020 (Released:2020-04-11)

参考文献数

18

被引用文献数

1

---

Using long-term high-resolution operational radiosonde observation data from nine stations in the subtropics and mid-latitudes of Japan, this study performed statistical analysis of the dynamical characteristics of gravity waves (GWs). Wave generation by shear instability in summer was a particular focus because orographic GWs cannot propagate deep into the middle atmosphere through their critical layer in the lower stratosphere. The kinetic energy of summer stratospheric GWs is markedly large south of 37°N. Hodograph analysis revealed that GWs propagating eastward relative to the ground are dominant in summer. The percentage of GWs propagating energy upward (downward) is large above (below) the height at which the mean occurrence frequency of shear instability is high. The time series of the kinetic energy of stratospheric GWs exhibited statistically significant positive correlation with the occurrence frequency of shear instability slightly below the tropopause. These findings strongly suggest the possibility of excitation of summer stratospheric GWs by shear instability above the jet. The shear instability condition is satisfied more frequently in the region 30°N-35°N. This is probably related to two characteristics of the background fields slightly below the tropopause: larger vertical shear of zonal winds at higher latitudes and lower static stability at lower latitudes.

著者

Kozo Okamoto Hiromi Owada Tadashi Fujita Masahiro Kazumori Michiko Otsuka Hiromu Seko Yoshifumi Ota Naotaka Uekiyo Hiroshi Ishimoto Masahiro Hayashi Haruma Ishida Akiyoshi Ando Masaya Takahashi Kotaro Bessho Hironobu Yokota

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.162-168, 2020 (Released:2020-09-05)

参考文献数

21

被引用文献数

14

---

To discuss the feasibility of the Himawari follow-on program, impacts of a hyperspectral sounder on a geostationary satellite (GeoHSS) is assessed using an observing system simulation experiment. Hypothetical GeoHSS observations are simulated by using an accurate reanalysis dataset for a heavy rainfall event in western Japan in 2018. The global data assimilation experiment demonstrates that the assimilation of clear-sky radiances of the GeoHSS improves the forecasts of the representative meteorological field and slightly reduces the typhoon position error. The regional data assimilation experiment shows that assimilating temperature and relative humidity profiles derived from the GeoHSS improves the heavy rainfall in the Chugoku region of western Japan as a result of enhanced southwesterly moisture flow off the northwestern coast of the Kyushu Island. These results suggest that the GeoHSS provides valuable information on frequently available vertically resolved temperature and humidity and thus improves the forecasts of severe events.

著者

Kosuke Ito Hana Ichikawa

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.17A-001, (Released:2020-08-31)

被引用文献数

7

---

One of the remarkable environmental characteristics of tropical cyclone (TC) Hagibis (2019) was the positive sea surface temperature (SST) anomaly observed in the western North Pacific Ocean. In this study, an ensemble-based sensitivity experiment was conducted with a nonhydrostatic model, focusing on the impact of SST on TC motion. The TC with the analyzed SST (warm run) moved faster near mainland Japan than with the lowered SST (cold run), as the TC in the warm run was embedded earlier in the mid-latitude westerly jet located to the north than that in the cold run. The TC displacement was consistent with the large decrease of geopotential height at 500-hPa (Z500) in the north of TC Hagibis during the warm run. Further investigation showed that the approach to the westerly jet presumably induced the low local inertial stability as well as the southwesterly vertical wind shear enhancing the upward mass flux in the north of the TC. They led the enhanced upper-tropospheric northward outflow from the TC energized by the warm SST, and it resulted in the decrease of the Z500 in the north. This study suggests that warm SST can affect TC tracks through interaction with mid-latitude westerly jets.

著者

Munehiko Yamaguchi Hiromi Owada Udai Shimada Masahiro Sawada Takeshi Iriguchi Kate D. Musgrave Mark DeMaria

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.14, pp.138-143, 2018 (Released:2018-10-06)

参考文献数

22

被引用文献数

1 15

---

This study investigates prediction of TC intensity in the western North Pacific basin using a statistical-dynamical model called the Statistical Hurricane Intensity Prediction Scheme (SHIPS), with data sources in operations at the Japan Meteorological Agency (JMA) such as the JMA/Global Spectral Model forecast fields. In addition to predicting the change in the maximum wind (Vmax) as in the original SHIPS technique, another version of SHIPS for predicting the change in the minimum sea-level pressure (Pmin) has been developed. With 13 years of training samples, a total of 26 predictors were selected from among 52 through stepwise regression. Based on three years of independent samples, the root mean square errors of both Vmax and Pmin by the 26-predictor SHIPS model were found to be much smaller than those of the JMA/GSM and a simple climatology and persistence intensity model, which JMA official intensity forecasts are currently mainly based on. The prediction accuracy was not sensitive to the number of predictors as long as the leading predictors were included. Benefits of operationalizing SHIPS include a reduction in the errors of the JMA official intensity forecasts and an extension of their forecast length beyond the current 3 days (e.g., 5 days).

著者

Kohei Fukuda Kazuaki Yasunaga Ryo Oyama Akiyoshi Wada Atsushi Hamada Hironori Fudeyasu

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.109-114, 2020 (Released:2020-07-01)

参考文献数

22

---

This study examined the diurnal cycles of brightness temperature (TB) and upper-level horizontal winds associated with tropical cyclones (TCs) over the western North Pacific basin, making use of data retrieved from geostationary-satellite (Himawari-8) observations that exhibited unprecedented temporal and spatial resolutions. The results of a spectral analysis revealed that diurnal cycles prevail in TB variations over the outer regions of TCs (300-500 km from the storm center). The dominance of the diurnal cycle was also found in variations in the radial wind (Vr) in intensive TCs, although there was no dominant cycle in tangential wind variation. In addition, coherence spectra demonstrated that the diurnal cycles of TB and Vr are significantly coupled in intensive TCs. The migration speed of TB and Vr anomalies exceeded the time-mean Vr, and it was speculated that diurnal cycle signals propagate (i.e., are not advected) toward the outer regions of TCs.

著者

Satoru Yokoi

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16A, no.Special_Edition, pp.1-5, 2020 (Released:2020-06-13)

参考文献数

19

被引用文献数

4

---

Given vigorous mean diurnal variation (MDV) of cumulus convection and surface wind over coastal waters of the Indonesian Maritime Continent, surface sensible and latent heat fluxes (SHF and LHF) are expected to also exhibit significant MDV. However, it is difficult to grasp characteristics of MDV of these fluxes due to lack of surface observation data. Recently, two intensive observation campaigns were conducted off the west coast of Sumatra Island in austral summer, which offer us a unique opportunity to examine the characteristics of convection and the fluxes. This study analyzes these observations to reveal that the MDV of both SHF and LHF has considerable amplitude compared with the average. The MDV of SHF is primarily caused by that in surface air temperature, which is due to the MDV of convection. As for LHF, the MDV is primarily caused by that of surface wind speed, in which both the MDV of convection and sea/land breezes play roles. Furthermore, there are qualitative differences in the MDV of the fluxes between the two campaign periods, which can be explained from the viewpoint of differences in phase and intensity of MDV of convection and the sea/land breezes.

著者

Yanjie Li

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.92-96, 2020 (Released:2020-06-04)

参考文献数

43

被引用文献数

1

---

The meridional propagation of Rossby waves links different latitudes. Traditional wave propagation theory is mostly discussed in the non-divergent atmosphere. This work emphasizes the influence of the divergent effect on wave propagation by analyzing wave solutions to the linearized shallow-water quasi-geostrophic potential vorticity equation on the zonal mean flow. Changes in the basic-state quantities and wave solutions generated from consideration of the divergent effect are highlighted. Compared with the non-divergent situation, more waves are allowed to exist and propagate to much higher latitudes in the divergent case. The turning latitudes are generally moved northward when the divergent effect is included. This main conclusion is robust in the idealized super-rotational flow and 300 hPa climatological flows in winter and summer. The divergent effect also tends to slow the speed of wave propagation and favor waves reaching remoter longitudes. These finding implicates Rossby wave propagation with divergent effect may contribute more to the long-distance teleconnection than that in non-divergent case.

著者

Masato Sugi Yohei Yamada Kohei Yoshida Ryo Mizuta Masuo Nakano Chihiro Kodama Masaki Satoh

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.70-74, 2020 (Released:2020-05-01)

参考文献数

22

被引用文献数

31

---

In relation to projections of tropical cyclone (TC) frequency in a future warmer climate, there is a debate on whether the global frequency of TC seeds (weak pre-storm vortices) will increase or not. We examined changes in the frequency of TC seeds by occurrence frequency analysis (OFA) of vortex intensity (vorticity or maximum wind speed). We directly counted the number of vortices with various intensities in high resolution global atmospheric model simulations for present and future climates. By using the OFA we showed a clear reduction of the occurrence frequency of TC seeds and relatively weak (category 2 or weaker) TCs in a future warmer climate, with an increase in the frequency of the most intense (category 5) TCs. The results suggest that the OFA is a useful method to estimate the future changes in TC frequency distribution ranging from TC seeds to the most intense TCs.

著者

Satoru Yoshida Sho Yokota Hiromu Seko Tetsu Sakai Tomohiro Nagai

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.43-50, 2020 (Released:2020-03-07)

参考文献数

19

被引用文献数

9

---

We conducted observation system simulation experiments (OSSE) to investigate the effects of water vapor vertical profiles observed by Raman lidar (RL) on forecasts of heavy precipitation in Hiroshima, Japan, on August 19, 2014 using a local ensemble transform Kalman filter. We employed a simulation result similar to reality as nature-run (NR) and performed two OSSEs. In the first experiment (DaQv), conventional observation data and vertical profiles of water vapor mixing ratio in air (qv) estimated from NR were assimilated. In the second experiment (CNTL), only conventional observation data were assimilated. In DaQv, we assumed that the RL was in the low-level inflow that supplied water vapor to the heavy precipitation in Hiroshima. Assimilating qv for several hours increased qv around the RL observation station, especially at low level. The regions modified by the assimilation of qv moved to Hiroshima by low-level inflow, resulting in 9-hour precipitation being approximately 28% greater than that of CNTL, and was thus closer to that of the NR. The OSSEs suggest that water vapor RL observations on the windward side of the heavy precipitation are a useful approach for improving precipitation forecasts.

著者

Yasumitsu Maejima Takemasa Miyoshi

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.37-42, 2020 (Released:2020-02-23)

参考文献数

19

被引用文献数

4

---

This study aims to investigate the tradeoff between the computational time and forecast accuracy with different data assimilation (DA) windows of four-dimensional local ensemble transform Kalman filter (4D-LETKF) for a single-case severe rainfall event. We perform a series of Observing System Simulation Experiments (OSSEs) with 1-, 3-, 5- and 15-minute DA window in a severe rainstorm event in Kobe, Japan, on July 28, 2008, following the prior OSSEs by Maejima et al. (2019). Running 1-minute DA cycles showed the best forecast accuracy but with the highest computational cost. The computational cost could be reduced by taking a long DA window, but the forecast became less accurate even though the same number of observations were used. A significant gap was found between the 3-minute window and 5-minute window. With the 1- and 3-minute windows, the forecasts captured the intense rainfall, while with the 5-minute window or longer, the rainfall intensity was drastically underestimated. This single-case study suggests that 3-minute or shorter DA window be a promising method for a severe rainfall forecast, although more case studies are necessary to draw general conclusion.

著者

Tetsuya Takemi Takashi Unuma

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.30-36, 2020 (Released:2020-02-22)

参考文献数

23

被引用文献数

33

---

This study investigated the environmental factors responsible for the development of heavy rainfall in eastern Japan during the passage of Typhoon Hagibis (2019) by using mesoscale gridded analysis data as well as observed data. Environmental indices for diagnosing stability and moisture conditions were examined. It was found that the whole troposphere is almost saturated and the column total water vapor content is extremely large. In the lower troposphere we identified layers of moist absolutely unstable states with the thickness deeper than 2 km. Such deep moist absolutely unstable layers as well as abundant moisture content and almost saturated troposphere set a high potential for convective development. Under these favorable environmental conditions, the fact that the heights of the absolutely unstable layers' bottom are comparable to the mountain elevations is considered to be favorable for topographic lifting of unstable, moist air, which will trigger and activate strong convection and hence heavy rainfall. In spite of a moderate amount of convective available potential energy and a nearly moist-adiabatic lapse rate, moist absolute instability, abundant moisture, and high humidity jointly play a key role to increase the potential for generating the present heavy rainfalls.

著者

Daisuke Hatsuzuka Tomonori Sato Kohei Yoshida Masayoshi Ishii Ryo Mizuta

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.23-29, 2020 (Released:2020-02-14)

参考文献数

28

被引用文献数

12

---

This study investigated future changes in extreme precipitation associated with tropical cyclones (TCs) around Japan using large ensemble regional climate simulations for historical and +4 K climates. Under the warmer climate, extreme TC precipitation, defined as the 90th percentile value of the maximum daily precipitation derived from each TC (TCP90), is projected to increase throughout Japan from Kyushu to Kanto. We attributed most of the increase in TCP90 to increased atmospheric moisture due to global warming. Furthermore, it was found that TCP90 is projected to increase for all TC intensity categories. However, the projected increase in intense TCs affects TCP90 in only a limited area. Stronger TCs enhance TCP90 over east- and north-facing slopes of mountainous terrain, while TCP90 in most other areas is insensitive to TC intensity. These results suggest that even relatively weak TCs could have potential to produce extreme precipitation that might cause natural disasters.

著者

Tomomichi Ogata Hidenori Aiki

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.15, pp.262-267, 2019 (Released:2019-12-27)

参考文献数

45

被引用文献数

4

---

This study makes a first attempt to apply the diagnostic scheme of Aiki et al. (2017) to the output of an ocean general circulation model (OGCM), in order to investigate the basin-wide pathway of equatorial and mid-latitude wave energy associated with intraseasonal variability in the Indian Ocean. The vertical mode decomposition shows that 90-day variability of the second baroclinic mode is dominant in a realistic OGCM experiment. For 90-day equatorial Kelvin wave (KW) and Rossby wave (RW), energy input by wind stress appears in the eastern equatorial Indian Ocean that is then transferred eastward by KWs along the eastern equatorial waveguide (while westward as RW off equator). For 30-day Mixed-Rossby Gravity waves (MRG), wave energy is transferred eastward while wave phase propagates westward that is consistent with the dispersion relationship of low-frequency MRG. The new diagnostic scheme is able to show, particularly for 30-day MRG, eastward energy fluxes along the equatorial waveguide, while the other schemes in previous studies (e.g. pressure flux, quasi-geostrophic flux) cannot show the direction of the group velocity of equatorial waves.

著者

Truong Van Thinh Phan Cao Duong Kenlo Nishida Nasahara Takeo Tadono

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.15, pp.28-31, 2019 (Released:2019-02-11)

参考文献数

23

被引用文献数

12

---

A land use/land cover map is an important input for different applications. However, the accuracy of land cover maps remains a great uncertainty and mapping accuracy assessment is not well-documented. The objective of this paper is to examine the relationship between overall accuracy and the number of classification classes by conducting a literature review of land cover/land use studies. The results revealed a weak negative correlation between the map's accuracy and the number of classes. The paper suggests a decrease of 0.77% map's overall accuracy with respect to the increase of 1 land cover class. The average overall accuracy produced by 05 sensor types does not show the big difference. In addition, high spatial resolution sensor such as Airborne might not be always advantageous for producing high overall accuracy map since its accuracy depends on several factors including the number of land cover classes.