Extreme Rainfall Mechanisms Exhibited by Typhoon Morakot (2009)

Moderate Typhoon Morakot (2009) became the most catastrophic typhoon in Taiwan on record. The MM5 numerical experiments with and without bogus data assimilation (BDA) were used to investigate the extreme rainfall mechanisms in Taiwan associated with the westbound typhoon. The BDA, based on 4DVAR, helps MM5 to maintain a more consolidated typhoon vortex and better predict the observed track after landfall, thus producing realistic extreme rainfall (about 2400 mm) at the southern and Central Mountain Range (CMR) of Taiwan. Severe rainfall in Taiwan is dominated by the CMR that hence modulates rainfall predictability

Assimilation of GPS Refractivity from FORMOSAT-3/COSMIC Using a Nonlocal Operator with WRF 3DVAR and Its Impact on the Prediction of a Typhoon Event

A nonlocal observation operator has been developed to assimilate GPS radio occultation (RO) refractivity with WRF 3DVAR. For simplicity, in the past GPS RO refractivity was often assimilated using a local observation operator with the assumption that the GPS RO observation was representative of amodel local point. Such an operator did not take into account the effects of horizontal inhomogeneity on the derived GPS RO refractivity. In order to more accurately model the observables, Sokolovskiy et al. (2005a) developed a nonlocal observation operator, which would take into account the effects of horizontal inhomogeneity on GPS RO measurements. This nonlocal observation operator calculates the integrated amount of the model refractivity along the ray paths centered at the perigee points. For comparative purposes, the nonlocal observation operator can be simplified by limiting the length of integration near the RO point. This is called the "local operator variant", which is equivalent to the original local operator except that the original one is performed with fixed tangent points at observation levels. For computational efficiency, assimilation using both the nonlocal operator and local operator variant now is performed with smear tangent points at the mean height of each model vertical level. In this study, the statistics of observation errors using both local and nonlocal operators were estimated based on WRF simulations. The observation errors produced by the nonlocal operator are about two times smaller than those generated by the local operator and in agreement with Sokolovskiy et al. (2005b)

Impact of GPS Radio Occultation Refractivity Soundings on a Simulation of Typhoon Bilis (2006) upon Landfall

Typhoon Bilis which struck Taiwan in July 2006 was chosen to assess the potential impact of GPS radio occultation (RO) refractivity soundings on numerical simulation using the WRF model. We found that this case elucidates the impact of the limited GPS RO soundings on typhoon prediction due to their favorable locations. In addition, on top of available precipitable water (PW) and near-surface wind speed from SSM/I data, we have also explored their combined impacts on model prediction

Numerical Simulation of Radioactive Pollutant Dispersion over Northern Taiwan: A Winter Case Study

本文探討盛行東北季風以及台灣北部複雜地形條件下近地污染面源的擴散過程。文中使用一中尺度數值模式來作數值模擬。此模式包含邊界層高階參數化、雲物理以及污染物濃度預報方程。模式模擬結果顯示，若污染源為大屯山脈迎風面核一、二廠走之面源，中尺度局部地形環流的平流及擴散過程不可避免地將輻射性污染物帶入大台北盆地。核一廠的污染物可經由淡水河谷及基隆河谷，而核二廠污染物主要是由基隆河谷，進入了大台北盆地。在強盛行風下，兩廠之污染物均越過林口台地並於三、四小時內影響桃園及新竹地區，平均地面濃度值則降為約原污染源濃度的十分之一。若考慮白日地面加溫作用，則因大氣邊界層迅速發展，盆地濃度可再被稀釋成百分之一。但在弱風且近地熱力穩定情況下，大台北盆地的最大濃度值可為污染源濃度一半以上。在東北季風情況下，核四廠對宜蘭地區則有較大的影響。本文個案模擬結果顯示，福祿數(Froude number)不失為了解北台灣山嶽氣流特徵（過山、繞山及偏射）之有用參數，水平平流作用亦大致決定污染物移動與幾何分佈情況，然而近地大氣亂流的垂直擴散作用實為決定地面濃度大小更重要的因子。 This study investigated diffusion processes of near-surface area pollutant sources over complex terrain of northern Taiwan under prevailing northeast monsoon. Numerical simulations were performed by a mesoscale numerical model which includes a high-order closure scheme of planetary boundary layer parameterization, cloud microphysics and the prognostic equation for pollutant concentration. Model simulation results showed that for area sources over the upstream side of Da-Tun Mountain Range, radioactive pollutants were inevitably taken into the metropolitan Taipei Basin thru advection and diffusion processes of local topographically-induced mesoscale circulations. Pollutants from Station I of nuclear energy plants can be brought into Taipei Basin thru Tan-Shul River and Kee-Long River, while pollutants from Station 2 entered mainly thru Kee-Long River. For stronger prevailing winds, pollutants from both stations can be flowed over Lin-Kou Table land and contaminate Tao-Yuan and ilsin-Chu by 3-4 hours with the ground-level pollutant concentration about one-tenth of the original source concentration. With the diurnal surface heating included, the concentration can be further reduced to about one-hundredth. The maximum concentration over Taipei Basin could retain more than one-half of the source intensity for weaker winds under stable conditions. For the prevailing northeast monsoon, I-Lan area was more affected by Station 4. The winter case results indicated that Froude number appears to be an effective parmeter for an understanding of the mountain flow behaviors (passing over, surrounding or deflecting) in northern Taiwan. Horizontal advection processes mostly controlled the pathways and geometric distributions of the pollutants, while vertical diffusion processes of the atmospheric turbulence near the surface was a more dominant factor for the deter mination of concentration magnitude

Childhood Albuminuria and Chronic Kidney Disease is Associated with Mortality and End-Stage Renal Disease

We do not yet fully grasp the significance of childhood albuminuria. Based on mass urinary screening (MUS) using albumin-specific dipsticks in school children, we studied the independent association of estimated glomerular filtration rate (eGFR) and albuminuria with mortality and end-stage renal disease (ESRD) in children with chronic kidney disease (CKD). Methods: A prospective cohort of 5351 children with albuminuria detected by school MSU during the period 1992–1996, followed up to 2009. Results: Cumulative mortality rate, prevalence of CKD, and ESRD were higher in children with albuminuria than those without. Albuminuria category was associated with the risk of mortality [hazard ratio (HR) 3.4] and ESRD (HR 3.24). Lower eGFR and albuminuria predicted mortality and ESRD among children with albuminuria and CKD. We found that being below a threshold of 45 mL/min/1.73 m2 was significantly associated with ESRD. The highest renal function decline, along with the steepest slope of cumulative ESRD number, occurred in Stage 3, the critical point in renal progression. Risk factors for renal progression among different age groups with albuminuria were hypercholesterolemia and low serum albumin at 7–17 years of age. Beyond 18 years of age, besides the risk factor, a higher fasting blood sugar (BS) was also noted. Conclusion: Childhood albuminuria is a risk factor for CKD in later life, albuminuria provides additional prognostic information, and complications of CKD should be defined in each case

Pachyonychia congenita: Report of two cases and mutation analysis

Pachyonychia congenita (PC) comprises a group of rare autosomal dominant genetic disorders that involve ectodermal dysplasia. It is characterized by hypertrophic nail dystrophy, focal palmoplantar keratoderma, follicular keratoses, and oral leukokeratosis. Historically, PC has been subdivided into two subtypes, PC-1 or PC-2, on the basis of clinical presentation. However, differential diagnosis based on clinical grounds, especially in young and/or not fully penetrant patients, can be difficult. In addition, clinical analysis of the large case series has shown that there is considerable phenotypic overlap between these two subtypes recently. Based on the advent of molecular genetics and the identification of the genes causing PC, more specific nomenclature has been adopted. Therefore, diagnosis at the molecular level is useful and important to confirm the clinical impression. In this report, we describe two typical cases of PC with mutation analysis revealed a small deletion (514_516delACC, Asn172del) and a point mutation (487 G > A, GAG → AAG, Glu163Lys) in the KRT6A gene

Anhidrotic ectodermal dysplasia—A case series in a medical center in southern Taiwan

Background: Anhidrotic ectodermal dysplasia (EDA) is a rare genodermatosis that causes developmental defects in ectoderm-derived structures. The clinical triad consists of hypodontia, hypotrichosis, and anhidrosis with other additional symptoms. The aim of this study is to summarize the clinical manifestations, family history, histopathological findings of the skin, and gene mutations in EDA patients who presented at a medical center in order to make the disease better known among medical personnel. Methods: A retrospective review of the medical charts and photographs of patients diagnosed with EDA at the Department of Dermatology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University from June 1988 through May 2011 was performed. Information about the clinical manifestations, family history, histopathological findings of the skin, and genetic mutations was collected, and the initial presenting symptoms that lead to seeking medical services were determined. Results: One female patient and seven male patients were identified. The triad was present in all patients, in addition to other variable features. Five patients had a positive family history, while three of them were from the same family. Histopathological findings noted in the skin biopsies included the absence of sweat glands on the palmar skin. Genetic mutations were detected in six of seven patients in this study, but there was no genotype-phenotype correlation. The initial presentations most commonly noted were the absence of sweating with episodic hyperthermia since birth. Eczema since infancy was the main reason why these patients visited the dermatology department following the diagnosis of EDA. Conclusions: EDA is a rare genodermatosis, and it is invariably characterized by its clinical triad. Family history and genetic analysis help in the diagnosis. The dermatologist, pediatrician, and dentist are usually the medical personnel that these patients first visit, and therefore these individuals should be acquainted with this disease in order to provide appropriate care

Exploring the Evolution of Typhoon Lekima (2019) Moving Offshore Northeast of Taiwan with a Multi-Resolution Global Model

Typhoon Lekima occurred in early August 2019 and moved northwestward toward Taiwan. During offshore passage, the typhoon underwent rapid intensification, with a northward deflected track, moving closer to northeastern Taiwan. A global model, MPAS, at a multi-resolution of 60-15-3 km, is utilized with ensemble forecasts to investigate the dynamic processes causing the track deflection and intensity change as well as identify the track uncertainty to initial perturbed conditions under the topographic effects of the Central Mountain Range (CMR). For spinning up the typhoon vortex in ensemble forecasts, dynamic vortex initialization has been enforced with a 3 km resolution targeted at the Taiwan area. As one specific member track is similar to the best track, the track deflection is significantly reduced in the absence of the Taiwan terrain, highlighting the role of the topographic effects of the CMR. For these tracks with similar deflection, the northward deflection is caused by the induced strong flow to the east of the typhoon center in response to the re-circulating flow around southern Taiwan, which produces the wavenumber-one gyre in the asymmetric flow difference to drive the vortex northward. The typhoon translation around the Taiwan terrain is dominated by the changing wavenumber-one horizontal potential vorticity (PV) advection during the track deflection in the ensemble forecasts. The formation of an intense PV tongue along the upper eyewall is a facilitation precondition of RI, while RI can be significantly enhanced in the presence of an intense lower-stratospheric PV core near the upper eye, which is produced by the radial inflow of the developed transverse vortex circulation over the upper-level outflow layer

Exploring the Evolution of Typhoon Lekima (2019) Moving Offshore Northeast of Taiwan with a Multi-Resolution Global Model

Typhoon Lekima occurred in early August 2019 and moved northwestward toward Taiwan. During offshore passage, the typhoon underwent rapid intensification, with a northward deflected track, moving closer to northeastern Taiwan. A global model, MPAS, at a multi-resolution of 60-15-3 km, is utilized with ensemble forecasts to investigate the dynamic processes causing the track deflection and intensity change as well as identify the track uncertainty to initial perturbed conditions under the topographic effects of the Central Mountain Range (CMR). For spinning up the typhoon vortex in ensemble forecasts, dynamic vortex initialization has been enforced with a 3 km resolution targeted at the Taiwan area. As one specific member track is similar to the best track, the track deflection is significantly reduced in the absence of the Taiwan terrain, highlighting the role of the topographic effects of the CMR. For these tracks with similar deflection, the northward deflection is caused by the induced strong flow to the east of the typhoon center in response to the re-circulating flow around southern Taiwan, which produces the wavenumber-one gyre in the asymmetric flow difference to drive the vortex northward. The typhoon translation around the Taiwan terrain is dominated by the changing wavenumber-one horizontal potential vorticity (PV) advection during the track deflection in the ensemble forecasts. The formation of an intense PV tongue along the upper eyewall is a facilitation precondition of RI, while RI can be significantly enhanced in the presence of an intense lower-stratospheric PV core near the upper eye, which is produced by the radial inflow of the developed transverse vortex circulation over the upper-level outflow layer