scholarly journals Preliminary assessment for sub-seasonal to seasonal precipitation model on four specific conditions over western Indonesia

2021 ◽  
Vol 893 (1) ◽  
pp. 012045
Author(s):  
Agita Vivi ◽  
Rahmat Hidayat ◽  
Akhmad Faqih ◽  
Furqon Alfahmi
Keyword(s):  
Performance Comparison ◽  
Precipitation Pattern ◽  
Wet Season ◽  
Preliminary Assessment ◽  
Precipitation Model ◽  
Daily Precipitation Data ◽  
Spatial Performance ◽  
Monthly Period ◽  
Perturbed Model ◽  
Better Than

Abstract Preliminary assessment of sub-seasonal to seasonal reforecast precipitation model (S2S) was conducted to analyze the model's performance over western Indonesia on four conditions. The ECMWF S2S model was compared to quality controlled daily precipitation data from 645 observation points over the region. The control and perturbed model for the first three time steps and the last three were utilized to obtain the best performance comparison. The analysis was conducted in monthly period, MJO events, NCS events, and when both of them were active during period of November-December-January-February (NDJF) from 1998 to 2017. The results show that the first three time steps perform much better than the last one with a slightly higher correlation coefficient from the control model with relatively similar RMSE in Natuna Islands. Spatial analysis indicates that both of the control and perturbed models can catch the variation brought by the wet season in the NDJF period, by the MJO, show a hint of NCS effect, and the combination when MJO and NCS were active at the same time. The models can depict the precipitation pattern pretty well with the tendency to overestimate low rainfall intensity and underestimate the high one. The models relatively overestimate the intensity in Sumatra for the whole period. Meanwhile, consistently good spatial performance is shown by the models over Java, both in NDJF periods or MJO events.

Types and amounts of the precipitation changes in recent 50 years of the Babao River basin

2021 ◽  
Author(s):  
Guanxing Wang ◽  
Fan Zhang
Keyword(s):  
River Basin ◽  
Precipitation Amount ◽  
Precipitation Pattern ◽  
The Tibetan Plateau ◽  
Wet Season ◽  
Local Agriculture ◽  
Changing Trend ◽  
Precipitation Type ◽  
Monthly Changes ◽  
Precipitation Changes

<p>Being an important water resource of the local and downstream living hoods, precipitation amount is experiencing drastic changes in the Babao River basin in the northeast of the Tibetan Plateau. Precipitation types also have great impacts on the runoff. However, in usual cases, weather stations only record precipitation amount without discriminating its type. Here, we compared results from three methods at improving precipitation type (solid and liquid) estimation with discontinuous 24 years precipitation type records of the Qilian gauging station. The results (bias rank of the three methods is 2.5% < 17.3% < 20.1%) showed that the estimation of different thresholds for wet season (4 °C) and dry season (5.5 °C) is the closest to the actual records. Based on the precipitation type distinction, the precipitation type and its amount changing trend in recent 50 years of the Babao River basin was examined. On average, snowfall accounts for 10.7% in whole year, and mainly happens in March, April, May and October (8.9% in whole year). In the context of climate warming, the annual precipitation and rainfall increasing significantly while the annual snowfall decreased slightly. Furthermore, on the perspective of monthly changes, rainfall amounts of May and August enhanced significantly while snowfall amount decreased significantly in June and September. The above conclusions indicated the warming climate also changed the precipitation pattern in the Babao River basin which would likely cause drought in the spring season and bring challenge to the local agriculture.</p>

scholarly journals A Preliminary Assessment of the “Undercatching” and the Precipitation Pattern in an Alpine Basin

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1061 ◽  
Author(s):  
Patricia Jimeno-Sáez ◽  
David Pulido-Velazquez ◽  
Antonio-Juan Collados-Lara ◽  
Eulogio Pardo-Igúzquiza ◽  
Javier Senent-Aparicio ◽  
...  
Keyword(s):  
Sierra Nevada ◽  
Hydrological Model ◽  
Precipitation Pattern ◽  
Wind Fields ◽  
Preliminary Assessment ◽  
Alpine Regions ◽  
Temperature And Precipitation ◽  
Geostatistical Approach ◽  
Geostatistical Techniques ◽  
Two Parameters

Gauges modify wind fields, producing important systematic errors (undercatching) in the measurement of solid precipitation (Ps), especially under windy conditions. A methodology that combines geostatistical techniques and hydrological models to perform a preliminary assessment of global undercatch and precipitation patterns in alpine regions is proposed. An assessment of temperature and precipitation fields is performed by applying geostatistical approaches assuming different hypothesis about the relationship between climatic fields and altitude. Several experiments using different approximations of climatic fields in different approaches to a hydrological model are evaluated. A new hydrological model, the Snow-Témez Model (STM), is developed including two parameters to correct the solid (Cs) and liquid precipitation (Cr). The procedure allows identifying the best combination of geostatistical approach and hydrological model for estimating streamflow in the Canales Basin, an alpine catchment of the Sierra Nevada (Spain). The sensitivity of the results to the correction of the precipitation fields is analyzed, revealing that the results of the streamflow simulation are improved when the precipitation is corrected considerably. High values of solid Cs are obtained, while Cr values, although smaller than the solid one, are also significant.

scholarly journals Development of a Pressure–Precipitation Transmitter

2019 ◽  
Vol 58 (11) ◽  
pp. 2453-2468
Author(s):  
Masaru Inatsu ◽  
Tamaki Suematsu ◽  
Yuta Tamaki ◽  
Naoto Nakano ◽  
Kao Mizushima ◽  
...  
Keyword(s):  
Regression Model ◽  
Daily Precipitation ◽  
Reanalysis Data ◽  
Precipitation Pattern ◽  
Multilevel Regression ◽  
Extreme Statistics ◽  
Spatial Continuity ◽  
Daily Precipitation Data ◽  
Multilevel Regression Model

AbstractA novel method is proposed to create very long term daily precipitation data for the extreme statistics by computing very long term daily sea level pressure (SLP) with the SLP emulator (a statistical multilevel regression model) and then converting the SLP into precipitation by combining statistical downscaling methods of the analog ensemble and singular value decomposition (SVD). After a review of the SLP emulator, we present a multilevel regression model constructed for each month that is based on a time series of 1000 principal components of SLPs on global reanalysis data. Simple integration of the SLP emulator provides 100-yr daily SLP data, which are temporally interpolated into a 6-h interval. Next, the pressure–precipitation transmitter (PPT) is developed to convert 6-hourly SLP to daily precipitation. The PPT makes its first-guess estimate from a composite of time frames with analogous SLP transition patterns in the learning period. The departure of SLPs from the analog ensemble is then corrected with an SVD relationship between SLPs and precipitation. The final product showed a fairly realistic precipitation pattern, displaying temporal and spatial continuity. The annual-maximum precipitation of the estimated 100-yr data extended the tail of probability distribution of the 8-yr learning data.

scholarly journals Performance Comparison of the Optimized Inverted Joined Wing Airplane Concept and Classical Configuration Airplanes

2016 ◽  
Vol 63 (3) ◽  
pp. 455-470 ◽  
Author(s):  
Adam Sieradzki ◽  
Adam Dziubiński ◽  
Cezary Galiński
Keyword(s):  
Performance Prediction ◽  
Performance Comparison ◽  
Cfd Models ◽  
Induced Drag ◽  
Computational Fluid Dynamics Cfd ◽  
Front Wing ◽  
New Research ◽  
Joined Wing ◽  
Real Scale ◽  
Better Than

Abstract The joined wing concept is an unconventional airplane configuration, known since the mid-twenties of the last century. It has several possible advantages, like reduction of the induced drag and weight due to the closed wing concept. The inverted joined wing variant is its rarely considered version, with the front wing being situated above the aft wing. The following paper presents a performance prediction of the recently optimized configuration of this airplane. Flight characteristics obtained numerically were compared with the performance of two classical configuration airplanes of similar category. Their computational fluid dynamics (CFD) models were created basing on available documentation, photographs and some inverse engineering methods. The analysis included simulations performed for a scale of 3-meter wingspan inverted joined wing demonstrator and also for real-scale manned airplanes. Therefore, the results of CFD calculations allowed us to assess the competitiveness of the presented concept, as compared to the most technologically advanced airplanes designed and manufactured to date. At the end of the paper, the areas where the inverted joined wing is better than conventional airplane were predicted and new research possibilities were described.

scholarly journals A Genetic Method using Hybrid Crossover for Solving Travelling Salesman Problem

2019 ◽  
Vol 8 (2) ◽  
pp. 5066-5072
Keyword(s):  
Hybrid Method ◽  
Nearest Neighbor ◽  
Travelling Salesman Problem ◽  
Performance Comparison ◽  
Initial Population ◽  
Genetic Approach ◽  
Comparison Standard ◽  
Travelling Salesman ◽  
Genetic Method ◽  
Better Than

This paper proposes a Genetic approach using Hybrid Crossover for Solving the Travelling Salesman Problem. Proposed hybrid method generates an initial population using Nearest Neighbor (NN) approach which is modified using “Sub-Path Mutation” (SPM) process. Modified population undergoes Distance Preserving Crossover (DPX) [2] and 2-opt Optimal mutation (2-opt) [1] to check for possible refinement. SPM searches position for the minimum distant city within a given path. This work is motivated by the algorithm developed by [3] who performed DPX and 2-opt mutation on the initial population generated using NN. For performance comparison, standard TSPLIB data is taken. The proposed hybrid method performances better in terms of % best error. It performs better than methods reported in [3 - 11].

scholarly journals Performance comparison of RSA and AES to SMS messages compression using Huffman algorithm

2020 ◽  
Vol 8 (3) ◽  
pp. 171-177 ◽  
Author(s):  
Laurentinus Laurentinus ◽  
Harrizki Arie Pradana ◽  
Dwi Yuny Sylfania ◽  
Fransiskus Panca Juniawan
Keyword(s):  
Performance Comparison ◽  
Short Message ◽  
Average Efficiency ◽  
Rsa Algorithm ◽  
Huffman Algorithm ◽  
Better Than

Improved security of short message services (SMS) can be obtained using cryptographic methods, both symmetric and asymmetric, but must remain efficient. This paper aims to study the performance and efficiency of the symmetric crypto of AES-128 and asymmetric crypto of RSA with message compression in securing SMS messages. The ciphertext of RSA and AES were compressed using the Huffman algorithm. The average AES encryption time for each character is faster than RSA, which is 5.8 and 24.7 ms/character for AES and AES+Huffman encryption and 8.7 and 45.8 ms/character for RSA and RSA+Huffman, from messages with 15, 30, 60 and 90 characters. AES decryption time is also faster, which is 27.2 ms/character compared to 47.6 ms/character in RSA. Huffman compression produces an average efficiency of 24.8 % for the RSA algorithm, better than 17.35 % of AES efficiency for plaintext of 1, 16, 45, and 88 characters.

scholarly journals Interannual and Intraseasonal Variations of the Onset and Demise of the Pre-Wet Season and the Wet Season in the Northern Northeast Brazil

2018 ◽  
Vol 33 (3) ◽  
pp. 472-484 ◽  
Author(s):  
Francisco das Chagas Vasconcelos Junior ◽  
Charles Jones ◽  
Adilson Wagner Gandu
Keyword(s):  
Late Onset ◽  
Southern Oscillation ◽  
Wave Train ◽  
South Atlantic Convergence Zone ◽  
Southeastern Brazil ◽  
Precipitation Pattern ◽  
Northeast Brazil ◽  
Tropical Atlantic ◽  
Wet Season ◽  
Sst Anomalies

Abstract The Northern Northeast Brazil (NNB) has two rainy periods, namely Pre-Wet Season (PWS) and Wet Season (WES), which are usually treated as one system. The precipitation pattern on NNB is influenced by sea surface temperature (SST) anomalies in the Atlantic and Pacific Ocean on interannual timescales particularly by the Interhemispheric Gradient of SST anomalies (IGS) and El Niño Southern Oscillation (ENSO). On intraseasonal time scales, the MJO is especially important. This study investigates the variability of the PWS/WES. The PWS is largely associated with the development of the South America Monsoon System and South Atlantic Convergence Zone (SAMS/SACZ); the onset is depicted by incursion of the SAMS/SACZ northward. Anomalous atmospheric cyclonic circulation over the southeastern Brazil along with easterlies over the northern Tropical Atlantic marks the early onset of the PWS, while easterlies over the southern Tropical Atlantic are related to late onset episodes. The demise of the PWS is significantly associated with propagation of the MJO, specifically during phases 4-5 of the MJO lifecycle. A Rossby wave train in 200-hPa geopotential height with positive anomalies over central-southern Brazil is depicted during transition between PWS and WES.

Dynamic Characteristic Analysis of Mega-Sub Controlled Structure with Friction Pendulum Bearings

2014 ◽  
Vol 926-930 ◽  
pp. 550-556
Author(s):  
Chang Xia ◽  
Da Bao Fu ◽  
Bin Huang ◽  
Li Ying Liu
Keyword(s):  
Friction Coefficient ◽  
Dynamic Characteristic ◽  
Performance Comparison ◽  
Control Effect ◽  
Characteristic Analysis ◽  
Structural Dynamic ◽  
Coefficient Increase ◽  
Controlled Structure ◽  
Friction Pendulum ◽  
Better Than

A novelty configuration of tall building structure, so-called mega-sub controlled structure (MSCS) with friction pendulum bearings (FPBs), which is featured by the FPBs at the bottom of sub-structures, is studied. The seismic responses of the MSCS with FPBs are carried out. The effects of the radius of the sliding surface and friction coefficient on structural dynamic characteristic indices, i.e. energy, acceleration, story displacement, story shear force, are analyzed. A performance comparison is made with the conventional MSCS. The results show that the MSCS with FPBs exhibits a better vibration-control effect than conventional MSCS. The controlling effectiveness of structure with radius of 500mm and 1500mm is better than that with radius of 1000mm and 2000mm. As the friction coefficient increase, the dynamic behaviors of structure tend to increase.

Sign in / Sign up

Export Citation Format

Share Document