Southern Tip Of Taiwan Research Articles

Stronger Intraseasonal Variability Observed Below the Seasonal Thermocline in the Kuroshio East of Taiwan During 2014 and 2015

AbstractIntraseasonal variability in the Kuroshio east of Taiwan was studied using moored observations at 23°N, 122°E from November 17, 2014 to September 5, 2015, high‐resolution ocean model data, and altimetry data. It is found for the first time that the observed meridional velocity has a peak signal at 50–60 days with a significant maximum variation at 200–600 m depth. Model outputs show that the 50–60‐day variability at the mooring station is related to meandering of the Kuroshio at 23°N. Both surface eddies, which can extend downward to ∼1,000 m depth, and coastal cold water upwelling associated with cyclonic eddies from deep layers can greatly change the isopycnal slope below ∼200 m depth at 23°N, 122°E, and their joint effect results in the maximum variation at 200–600 m depth. Ocean eddies southeast of Taiwan propagate northward along the current axis of the Kuroshio and have a large impact on intraseasonal variability. Case analysis indicates that the formation of ocean eddies or upwelling near the coast may be related to the Lüdao and Lanyu islands southeast of Taiwan or Kuroshio transport along the southern tip of Taiwan. In addition, the evolution of subsurface meridional velocity from mooring observations is inconsistent with that of the surface but is closely related to the evolution of local temperature below the seasonal thermocline. The maximum intraseasonal variability below the seasonal thermocline highlights the complex dynamics in the Kuroshio east of Taiwan.

Tide‐Induced Periodic Sea Surface Temperature Drops in the Coral Reef Area of Nanwan Bay, Southern Taiwan

AbstractTidal current‐induced cyclonic eddies cause cold‐water upwelling and periodic sea surface temperature (SST) drops around the coral reef area in Nanwan Bay, which is located at the southern tip of Taiwan. This study used Himawari‐8 satellite data and tide gauge and coastal ocean dynamics application radar (CODAR) data to analyze the characteristics of the SST drops and cyclonic eddy propagation and used an oceanic general circulation model (OGCM) to simulate the tidal current flowing process. According to the CODAR data analysis, the mixed primary semidiurnal tide had an average current velocity of 0.3–0.4 m s−1 throughout the bay, and the average life cycle of a cyclonic eddy is 6.6 hr, with a propagation speed of 0.35 m s−1. The SST drop during the spring tide period was greater than that during the neap tide period, and the SST dropped in both summer and winter. The average daily SST drop in the summer reached 2 °C with a maximum observed value of 4.7 °C, and the SST drop rate was 0.3–0.5 °C hr−1. The annual mean chlorophyll‐a concentration was 0.25 mg m−3. This study explored the special properties of the Nanwan Bay coral reef area from the perspective of ocean physics to allow ecologists to facilitate the implementation of long‐term conservation and monitoring programs.

Observation of internal tide-induced nutrient upwelling in Hungtsai Trough, a submarine canyon in the northern South China Sea

Temporal variations in hydrographic parameters and nutrients were observed in a 300m deep submarine canyon (Hungtsai Trough) near the southern tip of Taiwan. A vigorous oscillation below the surface layer has been observed which relates closely to an internal tidal wave generated from the nearby Luzon Strait. The vertical movement can be measured by monitoring an 18°C isothermal depth which shows an up-and-down oscillation between 90 and 240m with an average displacement of 110m within a tidal cycle, a scale significantly larger than has been reported elsewhere. The frequency of this oscillation coincides with the surface tide but in an almost opposite phase. All hydrographic and chemical parameters (oxygen, density, fluorescence, transmittance and nutrients including nitrate, phosphate and silicate) synchronize with the tidal movement, as judged by normalized plots against temperature. When the nutrient-rich deep water upwells and becomes an outcrop over the trough rim at 100m deep, it is swept horizontally by the strong alongshore tidal current. Consequently, the trough acts as a source point to supply extra nutrients to the coastal ecosystem.

Modeling study of three consecutive high ozone episodes over Taiwan in spring 2007

A three-dimensional photochemistry model is applied to analyze three unusual high O3 episodes that occurred continuously in Taiwan from May 1 to 11, 2007. During this period, the first high ozone episode was observed in northern and central western Taiwan on May 4. Following this episode, the second episode was observed throughout Taiwan on May 7, and continued for several days until May 10, when the third episode was observed in central western and southwestern Taiwan. This was the worst O3 period in Taiwan over the past two decades. During this period, 70% of the local air quality station reported an O3 concentration of over 120 ppb, and a maximum O3 concentration of 175 ppb was observed in background Taiwan.Based on model analyses, the sources of the three high O3 episodes differ. The high O3 concentration observed during the first episode is mainly attributed to the northeastward transport of O3 precursors and concentrations from northern and central western Taiwan under southwesterlies prior to frontal passage, chemically producing O3 over 30 ppb h−1 in northern Taiwan. During the second episode, horizontal advection of Asian outflow during the passage of an anticyclone and front contributes a maximum of 25 ppb h−1 in both northern and southern tip of Taiwan, respectively, increasing to more than 75 ppb h−1 in southwestern Taiwan because of the combination with the local source. During the third episode when the prevailing easterlies associated with a departing anticyclone to the east of Taiwan is blocked by the high central mountain, local O3 chemical production and horizontal transport contribute a maximum of 25 ppb h−1 and 35 ppb h−1 in central and southwestern Taiwan, respectively, under a calm and high background O3 condition.Source from Taiwan contributes more than half of the high O3 concentration over northwestern Taiwan prior to frontal passage during the first episode, but decreases to mostly below 40% over western Taiwan during the second episode when Asian outflow occurs, and increases to more than 60% over central and southwestern Taiwan due to pollution accumulation under an anticyclonic departure.

Air–water exchange fluxes of polycyclic aromatic hydrocarbons in the tropical coast, Taiwan

Air–water exchange fluxes of polycyclic aromatic hydrocarbons (PAHs) were simultaneously measured in air and water samples from two sites on the Kenting coast, located at the southern tip of Taiwan, from January to December 2010. There was no significant difference in the total PAH (t-PAH) concentrations in both gas and dissolved phases between these two sites due to the less local input which also coincided to the low levels of t-PAH concentration; the gas and dissolved phases averaged 1.29±0.59ngm−3 and 2.17±1.19ngL−1 respectively. The direction and magnitude of the daily flux of PAHs were significantly influenced by wind speed and dissolved PAH concentrations. Individual PAH flux ranged from 627ngm−2d−1 volatilization of phenanthrene during the rainy season with storm–water discharges raising dissolved phase concentration, to 67ngm−2d−1 absorption of fluoranthene during high wind speed periods. Due to PAH annual fluxes through air–water exchange, Kenting seawater is a source of low molecular weight PAHs and a reservoir of high molecular weight PAHs. Estimated annual volatilization fluxes ranged from 7.3μgm−2yr−1 for pyrene to 50μgm−2yr−1 for phenanthrene and the absorption fluxes ranged from −2.6μgm−2yr−1 for chrysene to −3.5μgm−2yr−1 for fluoranthene.

The impact of channel effect on Asian dust transport dynamics: a case in southeastern Asia

Abstract. A super heavy dust event was identified with unprecedented PM10 in terms of speed and concentration in the southeastern Asia. The average concentration was observed exceeding the value of 1000 μg m−3 for the duration lasting more than 10 h, with the highest value reached 1724 μg m−3 in northern Taiwan on 21 March 2010. We found that this case exhibited an uneven and intriguing spatial distribution of PM10 concentration and transport speed between eastern and western Taiwan. Higher values were observed in the western and northern areas. The peak concentrations can vary up to 5-fold between western and eastern Taiwan, and ten-fold between the northern tip and southern tip of Taiwan, only about 400 km apart. A high resolution, 10 km, numerical study by Weather Research Forecast (WRF) and WRF-chem models revealed that this intriguing spatial distribution of the Asian dust transport was resulting from a strong coupling effect of the geographic channel effect and blocking of the easterly from the Pacific Ocean. We are confident that this coupling effect can be revealed only by applying a high resolution numerical study in other similar regions.

Spring Migration of Chinese Goshawks (Accipiter soloensis) in Taiwan

Little is known about the abundance and distribution of Chinese Goshawks (Accipiter soloensis) during spring migration along the Western Pacific flyway around Taiwan. This species is the most numerous migratory raptor in East Asia. In April 2004, we employed weather radar at Kenting and Chiku to study the spatial and temporal distribution and flying behavior of migrants in the Taiwan area. Goshawk flocks migrating across Luzon Strait toward Taiwan (n = 193) averaged 3.1 km in length (SD = 3.41, range 1.0–27.5 km) and 0.7 km in width (SD = 0.30, range 0.3–2.5 km). Using a regression model relating bird numbers to the reflectivity of radar images, we estimated that at least 225 935 Chinese Goshawks passed through the study area during 5 d in the month of April. Flocks crossing the Luzon Strait approached the Hengchun Peninsula, at the southern tip of Taiwan, along several inland and offshore routes, making it difficult to obtain accurate and complete observations from the ground. Farther north at Chiku, we used radar imaging to estimate 150 619 northbound migrants, 67% of the number detected by the Kenting radar. Of these, 24% bypassed Taiwan and flew nonstop to mainland China via the Pescadores, located off the west coast of Taiwan. Another 55% flew over the southern end of Taiwan and then across the Taiwan Strait to the mainland. The remaining 21% continued north over Taiwan after spending up to 2 d in the central mountains of Taiwan. This likely explains why relatively small numbers of goshawks are observed in central and northern Taiwan. Chinese Goshawks flew more slowly and higher over land than over water, and their ground speed increased with favorable winds.

Reassessment of Permissible Negative Sequence Current for Power Plant Operation of Taipower

The N3 power plant of Taipower is located in the southern tip of Taiwan and connected to the power pool by four out-linking 345-kV overhead transmission circuits. There are two 951-MW generators. Each generator occupied 11% of the system peak load in 1985 when the generator was in commercial operation. Since Taipower is an isolated system, at the N-2 conditions, those generators were reduced to 75% loading to protect the power system. By the way, to avoid damage of negative sequence current (NSC), the limits of the N3 power plant are stricter than those in the IEEE Standard. However, in 2010, the capacity ratio of each generator in the plant to the system peak load has been reduced to 3% only. To increase the economic benefit of those generators, it is required to reassess the operation limits of NSC. EMTP was used to calculate the levels of NSC from the out-linking transmission circuits. From the results of this study, the effects of NSC could be ignored when the four out-linking circuits are in N-0, N-1, and N-2 conditions. The generators can be operated in full loading under these conditions. The modifications to the NSC limits of the N3 power plant are also suggested.

Settlement Patterns at Saqacengalj, a Slate House Settlement in Southern Taiwan

The present work combines archaeology, historical analysis, and ethnography to examine historical continuities in village social organization and settlement patterns in southern Taiwan in the mid- to late second millennium a.d. The focus of the work is Kau-shi village, located in Mu-dan County, Pin-dong District, at the southern tip of Taiwan. Its residents belong to the Southern Pai-wan Group, one of Taiwan’s indigenous populations. Kau-shi people moved and established new settlements six times before they settled on the current village. Their oldest abandoned settlement, Saqacengalj, is located about 7 to 8 km from the current village, an archaeological site covering about 1.4 acres with more than 83 stone structures dated to 500–600 years b.p . (before present), known previously through mystical folktale and oral tradition, and only recently through archaeology. Archaeological mapping of site layout and structural features found that the Saqacengalj settlement shares certain characteristics with later Pai-wan settlements extending into the twentieth century. However, there are certain features distinctly Saqacengalj from these settlements. In addition, a significant percentage of the 83 structures at Saqacengalj have a unique arrangement of small structures within the larger structure not found in later villages. These initial archaeological analyses suggest significant historical changes in the cultural and social meaning of village settlement patterns of the Southern Pai-wan Group over this half-millennium.

An active fault in southern Taiwan detected using shallow seismics and ground penetration radar

We conducted high-resolution shallow seismic exploration and ground penetrating radar (GPR) exploration to assess the earthquake hazard along the speculated north-south striking Chaujou Fault that is along the mountain foot at the western edge of the Central Range in the southern tip of Taiwan. Shallow seismic and GPR survey lines are approximately eastwest oriented, perpendicular to the speculated fault. All these survey lines run across the speculated fault. A fault plane of an 50° east-dipping angle is interpreted using shallow seismic profiles and one GPR profile. The interpreted fault locations are consistent with the scarp on the earth?s surface with an error of only a few meters, indicating that the scarp marks the Chaujou Fault?s surface location. The GPR profile even shows fault planes within a few meters depth, indicating fault rupturing within the past centuries. As Taiwan has humid climate with high erosion and deposition rate, these evidences imply that the Chaujou Fault really exists and is an active fault, that it has been displaced within the past centuries, and that it is a potential earthquake-inducing mechanism.

The Distribution and Habitats of the Pteris fauriei Complex in Taiwan

Polyploidization is a significant mode of speciation in plants. Polyploids often occupy habitats different from those of their diploid parents. In Taiwan, two varieties of Pteris fauriei, one diploid and one triploid, have been identified. The number of spores per sporangium and the size of spores are reliable indicators of ploidy. Diploid P. fauriei have 64-spore sporangia and the spores are significantly smaller than spores of triploid plants, which have 32-spore sporangia. Based on these findings, the distribution and habitats of the two cytotypes in Taiwan are characterized from both living plants and herbarium specimens. Altogether, 516 live plants from 32 locations and 76 herbarium specimens were analyzed. In general, diploid plants occur in warmer habitats than triploid plants. Diploid plants are widely distributed in Taiwan and nearby islands, but do not occur in central Taiwan nor in the Matsu islands. In contrast, triploid plants are not found in southern tip of Taiwan nor on islands west of central Taiwan. In northern Taiwan and on the west-central islands, diploids grow most often in exposed sites and grasslands. However, in southern Taiwan and islands Lanyu and Lutao, diploids also occur in woodlands. Triploids are restricted to grassland and woodland habitats in Taiwan, but grow in exposed sites, grassland and woodland habitats in Matsu islands. In general, triploids grow at higher elevations than the diploids.

Acceptance of the Mineralogical Society of America Roebling Medal for 2005

Mr. President, Ladies, and Gentlemen: Thank you very much for this great honor of receiving the Roebling Medal. This is also a humbling moment because I know the Medal actually belongs to the large high-pressure mineralogy community, including my many friends and mentors in the audience. I happened to be with the right people at the right time in the right place. The last time I counted, the total number of coauthors on all my publications reached 394. Adding the people who have helped but have not coauthored with me, the total must be over 1000. The field is very active and covers a diversity of applications as demonstrated by the dynamic scientific program, yesterday and today, organized by Bill Bassett, Yingwei Fei, Rus Hemley, and Anne Hofmeister. The field was not always this exciting, nor the future this clear when I started four decades ago. In fact I had serious doubts when I was an undergraduate student in the Geology Department of National Taiwan University. The on-going practice for senior thesis projects was to assign each student a 1:25,000 quadrangle for independent geological mapping. The mapping for the whole island was almost complete, and our Class of 1963 reached Hengchun Peninsula, the southern tip of Taiwan; a step further, and I would have to be an oceanographer. Although I understood that geology is more than mapping, I was still concerned about the future, and came to the U.S.A. where at least the area of land was considerably bigger. In 1964, I went to the University of Rochester, New York, and very fortunately, became the first Ph.D. student of two young assistant professors, Bill Bassett and Taro Takahashi, who had started a diamond-anvil cell (DAC) program to explore the Earth’s deep interior. The depth added a vast new dimension from …

Changes in the marine pollution management system in response to the Amorgos oil spill in Taiwan

The Marine Pollution Control Act ( MPCA) of Taiwan was promulgated on November 1, 2000, with the specific aim of controlling marine pollution, safeguarding public health, and promoting the sustainable use of marine resources. In addition to land-based pollution, oil spills are one of the most significant threats to the local marine environment largely on account of the some 30,000 tankers which pass through Taiwan’s coastal waters each year. In January 2001, two months after the enactment of this newly-introduced law, a Greek merchant vessel, the Amorgos ran aground in the vicinity of a national park on the southern tip of Taiwan, causing a serious oil spill and leading to considerable changes with regard to the marine pollution management system. The incident brought to the forefront many serious problems, such as a lack of experience, expertise as well as equipment required to respond to such disasters, as well as the ambiguous, unclear jurisdiction among related agencies. Thus, this paper reviews the incident of the Amorgos spill, identifies the major issues and lessons learned, and proposes several recommendations in an effort for Taiwan to further improve its marine pollution management system.

Seasonal growth dynamics of Laurencia papillosa and Gracilaria coronopifolia from a highly eutrophic reef in southern Taiwan: temperature limitation and nutrient availability

Both field and laboratory studies were used to investigate the effects of temperature limitation and nutrient availability on seasonal growth dynamics of Laurencia papillosa and Gracilaria coronopifolia from a nearshore coral reef in the southern tip of Taiwan during 1999–2000. L. papillosa was a summer blooming alga abundant in August–November and G. coronopifolia was abundant year round except April–May. L. papillosa blooms in the summer were attributed to its preference for high temperatures and highly sensitivity to low temperatures. A wider temperature range and a significant stimulation of growth by high N inputs can explain the appearance of G. coronopifolia year round and also its maximum growth in November–March. Levels of dissolved inorganic nitrogen (DIN) and soluble reactive phosphorus (SRP) in water column were extremely high, but the growth of these two rhodophytes still suffered nutrient limitation that the type and severity of nutrient limitation were variable over time and also between two species. The growth of L. papillosa was limited by P in the early growth stage (August–September) as indicated by decreased tissue P contents, increased C/P and N/P molar ratios and increased alkaline phosphatase activity (APA) and in the later growth stage, it was subjected to N-limitation, evidenced by decreased tissue N contents and C/P and N/P molar ratios and increased tissue P contents. The growth of G. coronopifolia was also P-limited as indicated by increased tissue N contents and concomitantly decreased tissue P contents, while marked drops in tissue P contents below the subsistence level in mid September and December 1999 reveal severe P limitation, which was supported by increased alkaline phosphatase activity. Higher critical nutrient contents and nutrient thresholds for maximum growth of G. coronopifolia suggest that G. coronopifolia faced more frequent nutrient limitation compared to L. papillosa. In conclusion, the results from these laboratory and field studies provide evidence that the seasonal abundance of L. papillosa and G. coronopifolia from southern Taiwan was determined by seasonal variations in seawater temperatures and nutrient concentrations as well as different physiological growth strategies. Seawater temperature and nutrient availability were important determinants of seasonal abundance of L. papillosa while the seasonal abundance of G. coronopifolia was influenced by nutrient availability.

Upwelling and Degree of Nutrient Consumption in Nanwan Bay, Southern Taiwan

The newly proposed Degree of Nutrient Consumption (DNC) of upwelled waters was used to evaluate the upwelling process in Nanwan Bay off the southern tip of Taiwan. DNC values were found to be low in subsurface waters or in newly upwelled waters. In general, a low DNC value was detected alongside other traditionally used upwelling indicators such as lower temperature, pH and % oxygen saturation but higher salinity, nutrients and chlorophyll a. On the other hand, the DNC value could be several times higher in aged upwelled water found in the surface layer.

Numerical Simulations with MM5 3DVAR Initialization

The recently developed MM5 three-dimensional variational (3DVAR) assimilation system at NCAR has been used to investigate influences of ingested sounding and ship observation data on numerical simulations of severe weather in the vicinity of Taiwan. Three weather events were simulated in this study, which include a Mei-Yu front in June 1998, Supertyphoon Bilis in August 2000 and Typhoon Nari in September 2001. For the Mei-Yu front, the simulated low-pressure system northeast of Taiwan is stronger. when the 3DVAR is performed during initialization. The simulated patterns of heavy rainfall just off the southern tip of Taiwan are also closer to observations for the run with 3DV AR. For the second case of Typhoon Bilis, both runs with and without 3DVAR show a northward bias in track upstream of eastern Taiwan. However, due to less northward track deflection, the simulated heavy rainfall in Taiwan for the 3DV AR run is in better agreement with observations. For the no-3DVAR run, the simulated Typhoon Nari consistently moves southwestward toward Taiwan but then makes an incorrect landfall at northwestern Taiwan. With 3DVAR, the track simulation is improved with a landfall position at northeastern Taiwan. During landfall, the associated could convection is enhanced as the intense vortex core is in confrontation with the leading edge of the Central Mountain Range (CMR) and its movement is slowed down along the northwestern coast. The combination of both compression and stagnation of the embedded convective system may explain the extremely intense rainfall in northern Taiwan. The feature of observed intense rainfall over the southwestern slope base of the C／MR is also captured, but the intensity is considerably underpredicted due to lagging and weakening of the vortex core at later -times for both runs with and without 30V AR. The track simulation at later times has also been improved in the 3DVAR run, but the associated geometric distributions of 72h accumulated rainfall amounts in general are similar to those without 3DVAR. In the typhoon experiment with a bogus vortex, the 3DVAR rum preserves the initial vortex, quite well. However, the rainfall and track simulations are not improved by the ingestion of the bogus vortex for both runs with and without 3DVAR.

Optical Identification of Gamma-Ray Bursts at Kenting Observatory

AbstractA remotely-controlled observing station, the Kenting Observatory, has been established in the Kenting National Park, at the southern tip of Taiwan. There are four observing systems at the Observatory: (1) a Meade 16-inch reflector with an SBIG spectrograph plus an SBIG STV; (2) an RC-16inch reflector with an FLI CCD; (3) a Celestron 14-inch with an ST-7E CCD; and (4) a Binocular system of two Canon F1.8 telephoto lens with two FLI CCDs. One of the scientific tasks of this observatory is to provide fast response to satellite alerts in the hopes of identifying the optical counterparts of Gamma-Ray Bursts (GRBs) via the global effort of GRB Coordinated Network (GCN). In this conference proceedings, we describe the instruments and the science projects being carried out in the Observatory.

Ground‐based observation of ozone, carbon monoxide, and sulfur dioxide at Kenting, Taiwan, during the PEM‐West B campaign

Intensive measurements of chemical species were conducted during February–March, 1994 at Renting, which is at the southern tip of Taiwan, in accord with the Pacific Exploratory Measurements in the western Pacific ocean (PEM‐West B) experiment. In general, frequent outbreaks of cold polar air mass dominated the synoptic weather pattern, which was led by a fast moving cold front and followed by steady northeasterly winds over the Taiwan region. There was frontal passage only eight times, each taking about 48 hours to complete. Steady northeasterly winds prevailed during most of the study period and were associated with a negligible diurnal variation of the chemical species. The median level of ozone, CO, and SO2 in the northeasterly wind was 45.7, 198, and 0.08 ppbv, respectively. Dramatic changes in the levels of O3, CO, and SO2 occurred during each frontal passage, which was characterized by a drop in the surface pressure, a swift change in the wind direction, and a reduction in the wind speed. The ozone level dropped from 40–55 ppbv to about 6–15 ppbv at 12–18 hours after the time of the surface pressure minimum, and then it took about 6–18 hours to be restored to its original level. In the meantime, the levels of CO and SO2 also decreased in the beginning but increased dramatically up to 400–556 ppbv and 1–9.51 ppbv, respectively, right after the frontal passage. Later on, their concentration dropped back to the original steady level in a northeasterly wind.

Germs of disaster: the impact of epidemics on Japanese military campaigns in Taiwan, 1874 and 1895.

This essay highlights the ways in which epidemics shaped Japanese military campaigns in Taiwan in 1874 and again in 1895, as well as subsequent colonial policy after 1895. I have focused on these particular campaigns because a vast body of source materials exists which allows us not only to understand the diseases which ravaged the Japanese forces, but also to determine their effects on particular battles and subsequent Japanese military, foreign and colonial policy. For example, during the 1874 campaign in the southern tip of Taiwan, of the approximately 5,990 men at risk, only 4 soldiers were killed in battle, while 20 succumbed to battle wounds and other injuries. In contrast, 547 men died of disease, particularly malaria. During the 1895 campaign, the Japanese force of just over 50,000 men suffered horrific losses due to epidemics, with 4,642 soldiers dying of diseses as opposed to 164 killed in battle and 515 wounded or injured. Although the Japanese quickly won the war against the resistance forces, their battle against Taiwan's epidemics had only just begun, as thousands of Japanese soldiers and civilians perished during the first ears of the Japanese Occupation era (1895-1945). The Japanese soon realized that they would have to solve Taiwan's public health problems if they were to have any hope of effectively governing their new colony. As a result some of the first regulations of the colonial government concerned sanitation and quarantine measures. All in all, Japanese colonial policy and its colonial modernization of Taiwan appear to have been significantly shaped by fear of the island's epidemics and the need to bring them under control.

A Study of Taiwan Background Atmosphere

In this paper, the field observation data collected by the research team of the Climate and Air-quality Taiwan Station (CATS) from June 1991-October1991 are analyzed. During this period, a mobile laboratory equipped with highly sensitive instruments was used to monitor the level of chemical species at Hsinwu, located on the northwestern coast, and at Kenting, at the southern tip of Taiwan. The results show that the mean hourly-averaged SO2 level at the rural northwestern coast was about 1-4ppbv. When the southwesterly prevailed, the background mean SO2 level in the Taiwan Strait was about 0.1-1ppbv, which represented a well-diluted air of anthropogenic origin possibly from southern Taiwan. The CO level was about 220-260ppbv during the later period. Meanwhile, at the southern tip of Taiwan, the measured ozone level varied with the movement of the large-scale airmasses. In September, each time a typhoon or a tropical depression approached, both the surface pressure and the ozone level dropped. The lowest hourly-averaged ozone level recorded was about 7ppbv. Meanwhile, the peroxyacetyl nitrate (PAN) level dropped with the decrease in ozone concentration, with the lowest level about 7pptv. On the other hand, in October, the continental High dominated, and the northeasterly prevailed. The ozone level varied between 38 and 50ppbv with an insignificant diurnal variation. Backward air-parcel tracing suggested that the observed high ozone level was associated with the airmass originating from regions of higher latitude near northern China, Korea and Japan. In all, Taiwan, being at the edge of eastern Asia and the western Pacific, is affected simultaneously by the polluted continental airmass and the clean maritime air. Current measurements have clearly supported this concept.