The global Very Long Baseline Interferometry observation for measuring the Earth rotation's parameters was launched around 1970s. Since then the precision of the measurements is continuously improving by taking into account various instrumental and environmental effects. The MHB2000 nutation model was introduced in 2002, which is constructed based on a revised nutation series derived from 20 years VLBI observations (1980–1999). In this work, we firstly estimated the amplitudes of all nutation terms from the IERS-EOP-C04 VLBI global solutions w.r.t. IAU1980, then we further inferred the BEPs (Basic Earth's Parameters) by fitting the major nutation terms. Meanwhile, the BEPs were obtained from the same nutation time series using a BI (Bayesian Inversion). The corrections to the precession rate and the estimated BEPs are in an agreement, independent of which methods have been applied.
<p>A space based relative radiometer has been developed and applied to the PICARD mission. It has successfully measured 37 months solar radiation, terrestrial outgoing radiation, and a comparable interannual variation in Earth Radiation Budget (ERB) is inferred from those measurements [1]. However, since the BOS (Bolometric Oscillation Sensor [2]) relative radiometer is originally designed to measure the solar irradiance with 10 seconds high cadence comparing to the absolute radiometer. The high dynamic range of BOS limits its performance to track the Earth&#8217;s outgoing radiation in terms of instantaneous field-of-view (iFOV) and the absolute radiation level. Two relative radiometers (RR) will be developed for JTSIM/FY-3F. One is the solar channel relative radiometer aimed to measure the solar irradiance side by side with the cavity solar irradiance absolute radiometer (SIAR). The second RR is acting as a non-scanner instrument to measure the Earth&#8217;s outgoing radiation. Comparing to the design of PICRD-BOS. Each RR has included an aperture, for the solar channel it limits its Unobstructed Field of View (UFOV) to about 1.5 degree and for the Earth channel to about 110 degrees, respectively. We also test the possibility to use the Carbon Nanotube coating on the main detector. In this presentation, the design of the earth channel relative radiometer (ERR) will be introduced, including the aperture design, dynamic range and the active temperature control system. The preliminary laboratory test result of the ERR will be discussed in the end.</p><p>[1] <strong>P. Zhu,</strong> M. Wild, M. van Ruymbeke, G. Thuillier, M. Meftah, and &#214;. Karatekin. Interannual variation of global net radiation flux as measured from space. J. Geophys. Res. doi:10.1002/2015JD024112, 121:6877&#8211;6891, 2016.</p><p>[2] <strong>P. Zhu,</strong> M.van Ruymbeke, &#214;. Karatekin, J.-P.No&#235;l, G. Thuillier, S. Dewitte, A. Chevalier, C. Conscience, E. Janssen, M. Meftah, and A. Irbah. A high dynamic radiation measurement instrument: the bolometric oscillation sensor (bos). Geosci. Instrum. Method. Data Syst., 4,89-98,:doi:10.5194/gi&#8211;4&#8211;89&#8211;2015, 2015.</p><p><strong>Acknowledgement</strong>: this work is partly supported by the National Natural Science Foundation of China No. 41974207 and CSC Scholarship No.202004910181</p><p>&#160;</p>
Ten 3-D cloud-resolving model (CRM) simulations and four 3-D limited area model (LAM) simulations of an intense mesoscale convective system observed on 23-24 January 2006 during the Tropical Warm Pool-International Cloud Experiment (TWP-ICE) are compared with each other and with observations and retrievals from a scanning polarimetric radar, colocated UHF and VHF vertical profilers, and a Joss-Waldvogel disdrometer in an attempt to explain a low bias in simulated stratiform rainfall. Despite different forcing methodologies, similar precipitation microphysics errors appear in CRMs and LAMs with differences that depend on the details of the bulk microphysics scheme used. One-moment schemes produce too many small raindrops, which biases Doppler velocities low, but produces rainwater contents (RWCs) that are similar to observed. Two-moment rain schemes with a gamma shape parameter (mu) of 0 produce excessive size sorting, which leads to larger Doppler velocities than those produced in one-moment schemes but lower RWCs. Two-moment schemes also produce a convective median volume diameter distribution that is too broad relative to observations and, thus, may have issues balancing raindrop formation, collision-coalescence, and raindrop breakup. Assuming a mu of 2.5 rather than 0 for the raindrop size distribution improves one-moment scheme biases, and allowing mu to have values greater than 0 may improve excessive size sorting in two-moment schemes. Underpredicted stratiform rain rates are associated with underpredicted ice water contents at the melting level rather than excessive rain evaporation, in turn likely associated with convective detrainment that is too high in the troposphere and mesoscale circulations that are too weak. A limited domain size also prevents a large, well-developed stratiform region like the one observed from developing in CRMs, although LAMs also fail to produce such a region.
A lunar narrow field of view radiometer (LNR) is designed to measure the short and long-wave radiation from a lunar orbiter as a part of the Lunar Research Program (AYAP-1) by the Turkish Space Agency. The flying model has been developed and constructed based on the heritage of previous space missions and the lunar short-and long-wave radiation values determined by the Diviner lunar radiometer. The LNR is targeting a high-resolution and accurate lunar albedo and surface radiation measurement with a lunar radiation flux measurement through optimized optical and thermal-mechanical design. The measurement of the single-pixel LNR will cover a broadband wavelength range from 0.2 to $\mathbf{50}.\mathbf{0}\ \boldsymbol{\mu} \mathbf{m}$ and a footprint of 3.45 km 2 at a 150 km altitude.
A station with limited motion antenna is usually used for the on-orbit control of a geostationary satellite. In order to enhance the capability of running a satellite, it is important to improve the orbit determination accuracy of the singlestation system. This paper presents a method for the orbit determination accuracy improvement with tracking and ranging data from a single station. This method includes two steps. The first step is improving antenna tracking accuracy by optimizing step tracking algorithm. Using big antennas or selecting mono-pulse tracking devices were paid more attention to improve tracking accuracy, which played an important role to reach good orbit determination accuracy in an orbit measurement campaign of a single station. While the influence of the antenna control unit software on orbit determination accuracy was neglected. This paper puts forward that the reformed tracking algorithm of the antenna control unit brings big improvement on tracking accuracy, which is derived from the comparison of orbit measurement results before and after software updating. The second step is to optimize the parameter settings of the orbit determination software. Reasonable weighted values are needed for orbit determination when using tracking and ranging data with different accuracies. Setting the weighted values according to their residual results of the orbit determination can utilize the measurement data with high precision sufficiently. The principal of 4σ should be adopted in eliminating limit setting of measurement data, which can make more than 99.98% data available. The orbit determination accuracy can be improved remarkably through the above method. For example, the orbit determination accuracy of a single station with a 13m limited motion antenna can achieve three-sigma position accuracy within 2km.
In Japan, the test transmission of satellite broadcasting started in 1984. It is expected that the spilt power will reach a wide area of the surrounding Japanese waters, even though the power is focused on the Japanese Islands. Thus it can be used as a convenient medium of information transmission to domestic vessels as well as for TV programs. The authors designed a device with a 2-axis automatic steering mechanism for onboard reception. The device has been used to measure the oceanic field strength of the transmitting satellites power and also for data reception from the Japanese meteorological satellite (CMS). Cloud images thus received offer important meteorological data which helps to infer the optimal route for ocean going vessels. The authors checked the tracking performance and also observed the field strength in the Pacific and Indian Oceans. They are also developing a positioning system for vessels steaming around the Japan's coastal sea using of domestic geostationary satellites.
A positive Earth Energy Imbalance (EEI) is the energy, which is continuously stored by the Earth and will ultimately released to the atmosphere, causing global warming. The "imperative to monitor Earth’s energy imbalance” (von Schuckmann et al., 2016) has been continuously reported by the Earth’s climate community. The EEI has been identified to be around 0.5 to 1.0 Wm−2. To determine its exact value both the Total Solar Irradiance (TSI) and the Top of the Atmosphere (ToA) Outgoing Radiation (TOR) need to be measured with unprecedented accuracy and precision.However, so far, the EEI could not be determined as the measurements were not sufficiently accurate. This calls for improved instrument technologies as well as a traceable calibration chain of the space instrumentation. To pave the way in that direction, the ISSI International Team "Towards Determining the Earth Energy Imbalance from Space" has been established. We collect the current knowledge of ERB measurements and identify missing elements for measuring EEI from space. Specifically, we collect past and ongoing measurements of the ERB components obtained with instruments such as CLARA, RAVAN, SIMBA, GERB, and CERES. The goal is to evaluate the performance and uncertainty of each of the instruments to identify observational challenges that need to be overcome to be able to measure both TSI and the Earth’s outgoing radiation with the required accuracy to ultimately be able to determine the absolute level of EEI from space.
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