First Assessment of HY-1C COCTS Thermal Infrared Calibration Using MetOp-B IASI

The Chinese Ocean Color and Temperature Scanner (COCTS) onboard the Haiyang-1C (HY-1C) satellite was launched in September 2018. Accurate and stable calibration is one of the important factors when deriving geophysical parameters with high quality. The first assessment of HY-1C COCTS thermal infrared calibration is conducted in this research. We choose the Infrared Atmospheric Sounding Interferometer (IASI) onboard the MetOp-B satellite as the reference instrument, mainly due to its hyper-spectral characteristic and accurate calibration superiority. The brightness temperatures (BTs) from the two HY-1C COCTS thermal infrared bands centered near 11 and 12 µm are collocated with the IASI in the spatial window of 0.12° × 0.12° and temporal window of half an hour. The homogeneity filtering of matchups is also carried out by setting the relative standard deviation (RSD) thresholds on each collocated grid and its neighboring grids. Based on the filtered matchups, the HY-1C COCTS BTs from the 11 and 12 µm channels are compared with IASI. The mean differences of COCTS minus IASI are 2.68 and 3.18 K for the 11 and 12 μm channels, respectively. The corresponding standard deviations (SDs) are also 0.29 and 0.28 K, respectively. In addition, the BT differences show latitude-dependence and BT-dependence. In order to correct the HY-1C COCTS thermal infrared BTs, the latitude-dependent coefficients are obtained to express the relationship between the BT differences and IASI BTs using the linear robust regression. After the BT correction, the biases and BT-dependence of the COCTS original BT minus IASI differences are removed. Further, the SDs decrease to 0.21 K for the 11 and 12 μm channels. Overall, the calibration of the HY-1C COCTS thermal infrared channels remains stable and the accuracy is around 0.2 K after inter-calibration.

SIMULASI PERGERAKAN RUNTUHAN LONGSOR MENGGUNAKAN MODEL SAVAGE-HUTTER DENGAN FINITE VOLUME METHOD

The avalanche is simulated using the Savage-Hutter model with Finite Volume Method (FVM) as a numerical solution in one dimension. The scheme used in FVM is collocated-grid. The aim of this research is to observe the avalanche based on different sediment types on the incline bed with the same initial sediment height. These simulations produce the value of velocity and height avalanche. For each type of sediment has a difference in velocity and height of avalanche affected by the internal angle of friction and the bed friction angle. Sediments with the highest bed friction angle have highest speed. The average velocity of each sediment are Quartz with u = 10.627, Yellow Sand with u = 7.437, and Rice with u = 2.1178 at time t = 1.

Numerical investigation of nanofluid turbulent flow in a wavy channel with different wavelengths, amplitudes & phase lag

Two dimensional incompressible turbulent nanofluid flow in a sinusoidal wavy channel is numerically investigated. Finite volume method and Rhie and Chow interpolation in a collocated grid arrangement are used for solving governing equations. The effects of the volume fraction of nanoparticles, Reynolds number, phase lag, frequency and amplitude of the wavy walls on the heat transfer rate are studied. The present work showed good agreement with existing experimental and numerical results. Increasing the frequency and amplitude of the wave and nanoparticles volume fraction has great effect on heat transfer rate.