Central Mountain Range Research Articles

A study on the structure and precipitation of Morakot (2009) induced by the Central Mountain Range of Taiwan

The three-dimensional structures and ingredients leading to extremely heavy precipitation associated with the passage of Typhoon Morakot (2009) over the Central Mountain Range (CMR) of Taiwan are investigated. Using a numerical model, the track, track deflection, characteristic rainbands, and precipitation patterns and maxima are successfully reproduced after verification against observational data. The high-level outward flow of the secondary circulation around the eyewall is not very clear even during Morakot’s strongest stage. In the control case, the eyewall collapses within 5 h after landfall that is closely associated with limited precipitation along the track after landfall. During the early stage of landfall, the deep convection on the windward (west) side of the CMR helps strengthening the secondary circulation. A quantitative comparison of total precipitable water, translation speed, and orographic lifting among 12 typhoons in recent years causing large accumulated rainfall in Taiwan shows that the abundant water vapor around Taiwan outweighs translation speed and orographic lifting in resulting in the record-breaking precipitation. It is found that the major processes leading to strong upward motion in the extremely heavy precipitation during 0000 UTC 8 August–0000 UTC 9 August are initiated by orographic lifting by CMR.

Diurnal Circulations and Rainfall in Taiwan during SoWMEX/TiMREX (2008)

Abstract The diurnal cycle of the local circulation, rainfall, and heat and moisture budgets is investigated in Taiwan's heavy rain (mei-yu) season using data from the 2008 Southwest Monsoon Experiment/Terrain-influenced Monsoon Rainfall Experiment (SoWMEX/TiMREX). Comparisons are made between an undisturbed (UNDIST; 22–29 May) and disturbed period (DIST; 31 May–4 June). Many aspects of the diurnal evolution in surface flows and rainfall were similar during both periods. At night and during early morning hours, the low-level southwesterly flow was deflected around Taiwan's main topographic barrier, the Central Mountain Range (CMR), with rainfall focused near areas of enhanced offshore confluence created by downslope and land-breeze flows. During the day, the flow switched to onshore and upslope, rainfall shifted inland, and deep convection developed along the coastal plains and windward slopes. Atmospheric budget analysis indicates a day-to-evening transition of convective structure from shallow to deep to stratiform. Evaporation associated with the evening/nighttime stratiform precipitation likely assisted the nocturnal katabatic flow. Though the flow impinging on Taiwan was blocked during both periods, a very moist troposphere and strengthened low-level oncoming flow during DIST resulted in more widespread and intense rainfall that was shifted to higher elevations, which resembled a more weakly blocked regime. Correspondingly, storm cores were tilted upslope during DIST, in contrast to the more erect storms characteristic of UNDIST. There were much more lofted precipitation-sized ice hydrometeors within storms during DIST, the upslope advection of which led to extensive stratiform rain regions overlying the CMR peaks, and the observed upslope shift in rainfall.

Habitat of the Vulnerable Formosan sambar deerRusa unicolor swinhoiiin Taiwan

AbstractThe sambar deerRusa unicoloris categorized as Vulnerable on the IUCN Red List because of continuous population decline across its native range. In Taiwan the Formosan sambar deerR. unicolor swinhoiiis listed as a protected species under the Wildlife Conservation Act because of human overexploitation. However, its population status remains unclear. We used presence and absence data from line transect and camera-trap surveys to identify key habitat variables and to map potential habitats available to this subspecies in Taiwan. We applied five habitat-suitability models: logistic regression, discriminant analysis, ecological-niche factor analysis, genetic algorithm for rule-set production, and maximum entropy. We then combined the results of all five models into an ensemble-forecasting model to facilitate a more robust prediction. This model indicated the existence of 7,865 km2of suitable habitat for the sambar deer. Distance from roads and elevation were identified as the most important environmental variables for habitat suitability, and deer preferred areas far from roads and > 1,500 m altitude. The results predicted that suitable deer habitat is mainly located in Taiwan's Central Mountain Range and Xue Mountain Range, with c. 70% of this suitable habitat in protected areas. However, the habitat predicted to be suitable is in five areas separated by mountain highways. We recommend that deer habitats close to the highways should be monitored for the future establishment of corridors between Formosan sambar deer sub-populations.

The Increased Contribution of Atmospheric Nitrogen Deposition to Nitrogen Cycling in a Rural Forested Area of Kyushu, Japan

Japan has been receiving increasing levels of atmospheric nitrogenous pollutants from the East Asian continent over the last few decades, so it is critical to evaluate the impact of this increased atmospheric nitro- gen (N) deposition on N cycling even in rural forests. Thisstudyevaluatedthecontributionofthecurrent level of atmospheric N deposition to N cycling in a rural forested area. Bulk precipitation and stream water were collected during 2007-2011 at the Shiiba Research Forest (SRF) located in the central Kyushu mountain range of southern Japan. Litterfall was also collected to investigate thecontributionofatmospheric N deposition to total N input (litterfall N+atmospheric N deposition). The results showed that atmospheric depositions of both nitrate (NO3 � ) and ammonium (NH4 + )w ere af ew times higher during 2009-2011 than in 1991. This could be the result of additional N deposition from the increased long-range transport of nitrogenous pollutants from the East Asian continent. The current level of annual N deposition (9.7 kg N ha �1 year �1 ) at the SRF was com- parable with that at many urban sites and was close to the reported threshold values causing N saturation in forest ecosystems. Although current atmospheric N deposition was an important component (23 %) of total N input (43 kg N ha �1 year �1 ) at the SRF, the concentrations of NO3 � in stream water were consistently low (<10 μmol L �1 ). These results indicate that atmospheric N deposition is currently largely incorporated into forest ecosystems without excess N export from forested watersheds.

Análisis climático de la precipitación anual e interanual en la cuenca media del río Grande de San Ramón, Costa Rica

Se investigan tres sectores ubicados en la Cuenca media del río Grande de San Ramón en Costa Rica que a pesar de encontrarse muy cerca unos de otros, éstos muestran variaciones espacio temporales en la precipitación anual e interanual. Dicha variación se atribuye a patrones de circulación atmosféricos que influyen anualmente, produciendo fuertes precipitaciones durante unos años, mientras que en otros, se da más bien una disminución. Pareciera que existe una mayor probabilidad que ocurran promedios bajos de precipitación anual durante los años El Niño y promedios altos durante los años La Niña. De esta forma, la fase cálida es más marcada en aquellos lugares de topografía plana, en valles, que tienen una mayor influencia marítima y de corrientes de viento, como son los casos de Palmares y San Ramón, no así el caso de Naranjo que se ubica en las faldas de la Sección de la Cordillera Volcánica Central. Por lo tanto, se manifiestan variaciones en distancias cortas, o sea no se muestra un comportamiento homogéneo aún en regiones pequeñas.

Quantification of Hortonian overland flow generation and soil erosion in a Central European low mountain range using rainfall experiments

In the framework of the EU-INTERREG-IVb-project ForeStClim (Transnational Forestry Management Strategies in Response to Regional Climate Change Impacts) a combination of experimental methods has been applied for the investigation of the spatial and temporal variation and intensity of overland flow generation and soil erosion processes.In the presented study, the influences of land-use type and land-management practices on overland flow generation and soil erosion are investigated for three low mountain range catchments in Luxembourg and in Rhineland-Palatinate, Germany. The key questions of the study can be summarized as follows: Can Hortonian overland flow generation be observed on all land-use types in the investigated areas in the Central European low mountain range? How can the contribution of forested areas to the flood and erosion dynamics be evaluated under humid climate conditions in Central Europe and what are the most important factors of influence? The results of the presented study show that forest areas can also be sources for overland flow and sediment, particularly artificial linear structures like unpaved roads and harvester tracks, where runoff coefficients between 41.2 and 97.1%, and erosion values between 2.6 and 122.5gm−2 were determined using rainfall experiments. Another important factor is soil water repellency, this factor can pre-eminently be observed under rather dry soil moisture conditions in summer and can have severe influence on overland flow generation particularly in forested areas. The results of the rainfall experiments in coniferous forests show runoff coefficients ranging from 0 to 86.9%, here the high values can all be traced back to water repellency influence, as the field observations suggest.In the context of flood generation, it is becoming more and more important to improve knowledge on overland flow generation and soil erosion processes occurring in forested catchments, particularly considering the expected climate change.

Origin and demographic history of the endemic Taiwan spruce (Picea morrisonicola)

Taiwan spruce (Picea morrisonicola) is a vulnerable conifer species endemic to the island of Taiwan. A warming climate and competition from subtropical tree species has limited the range of Taiwan spruce to the higher altitudes of the island. Using seeds sampled from an area in the central mountain range of Taiwan, 15 nuclear loci were sequenced in order to measure genetic variation and to assess the long-term genetic stability of the species. Genetic diversity is low and comparable to other spruce species with limited ranges such as Picea breweriana, Picea chihuahuana, and Picea schrenkiana. Importantly, analysis using approximate Bayesian computation (ABC) provides evidence for a drastic decline in the effective population size approximately 0.3–0.5 million years ago (mya). We used simulations to show that this is unlikely to be a false-positive result due to the limited sample used here. To investigate the phylogenetic origin of Taiwan spruce, additional sequencing was performed in the Chinese spruce Picea wilsonii and combined with previously published data for three other mainland China species, Picea purpurea, Picea likiangensis, and P. schrenkiana. Analysis of population structure revealed that P. morrisonicola clusters most closely with P. wilsonii, and coalescent analyses using the program MIMAR dated the split to 4–8 mya, coincidental to the formation of Taiwan. Considering the population decrease that occurred after the split, however, led to a much more recent origin.

Prevalence of fur mites (Acari: Atopomelidae) in non-human primates of Costa Rica

Parasites have been investigated for some New World primates; however, very little is known about ectoparasites and specifically fur mites. In this study, Alouatta palliata, Cebus capucinus, Saimiri oerstedii, and Ateles geoffroyi monkeys from different areas of Costa Rica were searched for fur mites. A total of 276 monkeys were evaluated, and 51 of them were positive for mites of the family Atopomelidae. Listrocarpus alouattae was identified on 22.3% of A. palliata; Listrocarpus capucinus on 12.8% of C. capucinus; and Listrocarpus costaricensis on 36.8% of S. oerstedii; No fur mites were found on A. geoffroyi. Sex was not considered a determinant of mite infestation, but prevalence was significantly higher in the Central Volcanic Mountain Range Conservation Area for L. alouattae (p=0.01) and in the Central Pacific Conservation Area for L. capucinus (p=0.002). These primate fur mites are highly host-specific. Differences in the geographical distribution may be due to monkey behavior and history, as well as to environmental conditions.

Analysis of the deep-seated gravitational slope deformations over Mt. Frascare (Central Italy) with geomorphological assessment and DInSAR approaches

A quantitative and innovative DGSD (deep gravitational slope deformation) assessment method that used integrated remote sensing was tested in the central Apennine mountain range (Italy). The movement rate was calculated for selected test areas using the differential SAR interferometry small baseline subset (SBAS) technique. The selected test areas were previously identified by interpreting both aerial photos and using 32 ERS radar images taken between 1993 and 2000. More than 15cm of cumulative surface displacement occurred across the Podalla DGSD along the satellite line of sight (LoS). Moreover, the displacement time series showed non-linear deformation rates, which included periods of accelerated movement correlated with strong rainfall. The high estimated Podalla DGSD activity indicates that this type of study should be conducted to monitor the evolution of this phenomenon. In addition, the DInSAR movement rate can be used to improve mapping and identify DGSDs in specific landscapes.

Recent changes in snow cover and evolution of supratimberline vegetation in the Puerto de los Neveros, Guadarrama Mountains (Spain)

The purpose of this study is to add more insight to the relationship between recent climate change and modifications in plant cover in supratimberline areas of Spain's Central Mountain Range. A 118 hectare study site was chosen at Puerto de los Neveros pass (2100 m) located on the ridge Peñalara (Montes Carpetanos), and between the high basins of the Lozoya and Eresma rivers. Historically, the pass is associated with the most abundant and long lasting snow accumulations in the Guadarrama Mountains, and with frequent use of the snow by local populations. A collection of sequenced aerial photographs of the plant cover was used to interpret the vegetation's spatial dynamics in relation to the evolution of thermal and snow depth variables recorded for the period 1951-2006 at the weather station at Puerto de Navacerrada. The significant value of the resulting coefficients confirms that plant cover at Puerto de los Neveros has been greatly affected by climate change, particularly by warmer winters, less snowfall and shorter snow duration, which have contributed to the shrinking surface area of snow hollows, high meadows and open shrublands and to the expansion of dense bush.

Applications of geographical information systems and remote sensing in natural disaster hazard assessment and mitigation in Taiwan

Geographic Information Systems (GISs) provide a powerful tool in managing and analysing spatial data. Geographic Information System has been applied successfully to large variety of fields, one field of particular interest is the field of disaster mitigation. The island of Taiwan is well known for the typhoons and earthquakes which in recent past has claimed lives and caused significant damage. It is well understood that hazard identification and land management play a major part in the reducing the impact of natural disasters. This is a role GIS is well suited to especially when combined with remote sensing data. This concept has been used throughout the world for purposes including identification of risk areas, real-time modelling of events and scenario modelling. Where this has the greatest potential in Taiwan is in the steep and rugged mountain areas of the Central Mountain Range which are sparsely populated and often difficult to access making conventional ground-based investigations impractical over large areas. Geographic Information System combined with remote sensing data provides the ability to effectively analyse various risk factors over large areas or inaccessible areas to identify localities which have the potential to be at higher risk from the impact of natural disasters.

A Study on Fault-Type and Site-Effect (VS30) Parameters in the Attenuation Relationships of Peak Ground Acceleration and Peak Ground Velocity in Ilan, Taiwan

The purpose of this study is to derive attenuation relationships of the peak ground acceleration (PGA) and peak ground velocity (PGV) in Ilan, Taiwan, including factors of fault type and site effect. A total of 2852 accelerograms recorded from 92 shallow earthquakes with Mw magnitude ranging from 4.0 to 7.7 are used to develop theregionalattenuationrelationships.Twomodelsareused:Model1usesrecordsfrom 65 strong-motion sites. The results will be especially useful for the Central Weather Bureau (CWB) early warning system to quickly assess and report the PGA and PGV maps for effective emergency-response operations. Model 2 uses records from the 46 strong-motion sites with available VS30 to incorporate a site-effect term, aiming to reduce the standard deviation of the predicted ground motion for engineering appli- cations. First, the results show that the fault-type amplification factor decreases faster with increasing magnitude for the strike-slip fault type than the reverse or normal fault types. In addition, from the intraevent residuals as function of distance of horizontal PGA for reverse earthquakes, we found clusters of higher PGAvalues at a distance of 110-130 km from events in southwestern areas. This was probably due to Moho re- flection along paths crossing the Central Mountain Range. Second, the PGVintraevent residual is more closely correlated with VS30 than that of the PGA because the latter is nota simple function ofVS30.Finally, bycomparing thestandard deviations ofthetotal residuals between the observed and predicted values before and after incorporating the fault-type and site-effect (VS30) terms, the change of standard deviation for PGA is 2.3%. In contrast, the PGV standard deviation is significantly decreased by about 11.6%. Evidently, the Model 2 attenuation relationships, especially for PGV, would be better suited for engineering applications.

Modificaciones climáticas y evolución de la cubierta vegetal en las áreas culminantes de la Sierra de Guadarrama (Sistema Central español) durante la segunda mitad del siglo XX : las altas cuencas del Ventisquero de La Condesa y de Valdemartín

The purpose of this study was to determine the relationship between recent climate changes and observed changes in the plant cover in the supraforest areas of the Central Mountain Range in Spain. Two small adjacent basins (La Condesa and Valdemartin) were selected as research sites at high altitude near a long-established national weather station at Puerto de Navacerrada in Sierra de Guadarrama. Aerial photograph interpretation was used to detect changes in vegetation at the sites in 1957, 1972, 1984, 1991 and 1998, and the results showed a correlation among the 18 climate-related parameters for the period 1951-2000. High index values and a basic similarity in tendencies confirmed that the extension of the plant facies had changed in accordance with variations in temperature and snow cover. As are result, it was determined that plant cover was sensitive to climate changes that had occurred during the study period and had responded by reducing the extent of the snowfields, hydrophytic meadows and open scrublands while expanding the pychroxerophytic meadows and dense scrublands.

Exocelina baliem sp. n., the only known pond species of New Guinea Exocelina Broun, 1886 (Coleoptera, Dytiscidae, Copelatinae)

Exocelina baliem sp. n. is described from the Baliem Valley in the Central Mountain Range of New Guinea (Papua Province, Indonesia). Having striolate elytra, different structure and setation of the male and female genitalia and tarsomeres, and inhabiting swampy ponds, the new species differs from all known New Guinea species, which have smooth elytra and are stream associated. It forms a monophyletic group with the Australian Exocelina ferruginea (Sharp, 1882) and New Caledonian Exocelina inexspectata Wewalka, Balke & Hendrich, 2010, based on shape of the paramere and structure of the male tarsi. Habitus, protarsomeres, and male and female genitalia are illustrated, comparing some structures with Exocelina ferruginea and two New Guinea stream species. We briefly discuss the biogeographic relevance of this discovery.

Sensitivity of typhoon track to asymmetric latent heating/rainfall induced by Taiwan topography: A numerical study of Typhoon Fanapi (2010)

Typhoon Fanapi (2010) traveled westward across the Central Mountain Range of Taiwan on 19 September and its rainfall shifted from a symmetric to an asymmetric pattern with convection mostly to the south and southeast. Meanwhile, the storm slowed down from 22 to 14 km h−1 for 12 h upon leaving Taiwan, and led to heavy rainfall (&gt;800 mm) and serious flooding over the low‐lying southwestern plains. Through simulation and sensitivity tests using the Cloud‐Resolving Storm Simulator at 3 km grid size, this study shows that the sudden and temporary speed reduction was caused by the asymmetric latent heating (LH), not the environmental flow. Specifically, over a 9 h period, the model storm moved westward at 16 km h−1 in the control run, but increasingly faster and more toward the northwest when the moisture (and thus the LH effect and its asymmetry) is gradually reduced. Steering flow analysis and estimation using model results suggest an eastward motion vector of about 8 km h−1, consistent with the observation, is produced by the asymmetric LH effect, when the effects from the vertical wind shear and beta‐drift are both taken into account. This result is further supported by the diagnosis on storm motion based on potential vorticity tendency. Although important, such feedback to typhoon track from rainfall asymmetry that is induced by the blocking effect of topography have not been reported or studied.

Morpho-Physical and Chemical Characteristics of Mountain Soils in Central Leyte

An important prerequisite to sustainable soil management is a good understanding of soil morphological, physical and chemical characteristics. Until now, very limited data are available on the characteristics of mountain soils in the central part of Leyte Island. Thus, this study was conducted to determine the morpho-physical and chemical characteristics of mountain soils derived from andesite and shale in central Leyte, and to evaluate the effects of parent material and topographic position on the properties of the soils. Eight soil profiles representing the dominant parent materials and topographic positions in the Abuyog-Mahaplag-Baybay portion of the central mountain range of the island were examined. Results revealed that the soils varied in their morphological, physical and chemical characteristics which to some extent reflect the nature of their parent material and the slope positions where they were formed. Soils derived from shale (Soil profiles 1, 2, 3 and 6) developed into young (Fluventric Eutropepts) and well-developed (Typic Hapludalfs) soils with generally moderate nutrient status. Soils derived from andesite (Soil profiles 4, 5, 7 and 8) developed into young (Typic Dystropepts) and well-developed (Typic Kandiudults) soils with generally low nutrient status. Regardless of parent material, soils on summit slope position tended to be better developed than soils on footslope and shoulder slope positions. The study showed that the influence of parent material on soil development was modified by the topographic position.

On the Geographic Asymmetry of Typhoon Translation Speed across the Mountainous Island of Taiwan

Abstract This paper examines the effect of topographically phase-locked convection on the motion of typhoons across the island of Taiwan. Data for 84 typhoons that reached Taiwan’s eastern coast from 1960 to 2010 are analyzed, with motions compared to the long-term average overland translation speed. For 61 continuous-track typhoons among all cases, 77% of the slow-moving tropical cyclones (TCs) made landfall on the northern end of Taiwan’s eastern coast, while 60% of the fast storms had southeastern coastal landfalls. This geographic asymmetry with respect to typhoon translation speeds widened after landfall, as the slow movers typically decelerated during the overland period, whereas the faster TCs sped up. In particular, the average overland duration was 16 h for the slow class, compared to only 3 h for the fast-moving typhoons. The combination of slower translation with longer duration for the northern class of TCs led to large rainfall on the southwestern slope of the island’s Central Mountain Range. Weather Research and Forecasting model experiments are used to study the effect of convection on storm motion over a mountainous island resembling Taiwan. The authors find that the topographically phase-locked convection acts to slow down (speed up) the northern (southern) landfalling typhoons. The model results also suggest that a positive feedback mechanism exists for the slow storms, in which the convective heating pattern forced by topography acts to reduce the TC motion, leading to even more prolonged precipitation and heating, yielding further speed reductions.

Provenance and geochronology of Cenozoic sandstones of northern Borneo

The Crocker Fan of Sabah was deposited during subduction of the Proto-South China Sea between the Eocene and Early Miocene. Collision of South China microcontinental blocks with Borneo in the Early Miocene terminated deep water sedimentation and resulted in the major regional Top Crocker Unconformity (TCU). Sedimentation of fluvio-deltaic and shallow marine character resumed in the late Early Miocene. The Crocker Fan sandstones were derived from nearby sources in Borneo and nearby SE Asia, rather than distant Asian and Himalayan sources. The Crocker Fan sandstones have a mature composition, but their textures and heavy mineralogy indicate they are first-cycle sandstones, mostly derived from nearby granitic source rocks, with some input of metamorphic, sedimentary and ophiolitic material. The discrepancy between compositional maturity and textural immaturity is attributed to the effects of tropical weathering. U–Pb ages of detrital zircons are predominantly Mesozoic. In the Eocene sandstones Cretaceous zircons dominate and suggest derivation from granites of the Schwaner Mountains of southern Borneo. In Oligocene sandstones Permian–Triassic and Palaeoproterozoic zircons become more important, and are interpreted to be derived from Permian–Triassic granites and Proterozoic basement of the Malay Tin Belt. Miocene fluvio-deltaic and shallow marine sandstones above the TCU were mostly recycled from the deformed Crocker Fan in the rising central mountain range of Borneo. The provenance of the Tajau Sandstone Member of the Lower Miocene Kudat Formation in north Sabah is strikingly different from other Miocene and older sandstones. Sediment was derived mainly from granitic and high-grade metamorphic source rocks. No such rocks existed in Borneo during the Early Miocene, but potential sources are present on Palawan, to the north of Borneo. They represent continental crust from South China and subduction-related metamorphic rocks which formed an elevated region in the Early Miocene which briefly supplied sediment to north Sabah.

Resurrection of Dendropemon sintenisii (Loranthaceae): an endemic mistletoe from Puerto Rico

On 25 November 1885 German botanist Paul Ernst Emil Sintenis collected a species of mistletoe in a coffee plantation in Aibonito, a municipality located in the central mountain range of Puerto Rico ( Sintenis 2856 , GOET). Ignatius Urban examined the specimen and name it Dendropemon sintenisii Krug & Urban (Urban 1897: 25) in honor of its collector. After its description D. sintenisii remained unknown in Puerto Rico and, although it was included in all major floristic treatments of the island, the species was a taxonomic ghost known only from the type specimen (Liogier 1985, Liogier & Martorell 2000, Axelrod 2011). No new specimens were labeled with the name in any herbarium since its original description and serious doubts existed among local botanists about its validity. This uncertainty resulted in the provisional placement of D. sintenisii under the synonymy of D. caribaeus Krug & Urban (Urban 1897: 27) in the recent monograph of Dendropemon by Kuijt (2011). This placement was justified because both the vegetative structures and infructescences of D. sintenisii share similarities with D. caribaeus , and the type specimen lacks flowers, which are key to confidently identify Dendropemon species (Kuijt 2011).

&lt;i&gt;Juncus kuohii&lt;/i&gt; (Juncaceae), a new species from Taiwan

Juncus kuohii , a new species from the central mountain range of Taiwan, is described and illustrated. It is compared morphologically to similar Juncus species in neighboring regions. An updated artificial key to Juncus species in Taiwan is also included.