Combining FY-3D MWTS-2 with AMSU-A Data for Inter-Decadal Diurnal Correction and Climate Trends of Atmospheric Temperature

Microwave temperature sounding observations from polar-orbiting meteorological satellites have been widely used for research on climate trends of atmospheric temperature at different heights around the world. Taking the Amazon rainforest as the target area, this study combined the Microwave Temperature Sounder-2 (MWTS-2) data onboard the Chinese FengYun-3D (FY-3D) satellite with the Advanced Microwave Sounding unit-A (AMSU-A) data onboard the National Oceanic and Atmospheric Administration (NOAA) and the European Meteorological Operational (MetOp) polar-orbiting meteorological satellites (i.e., NOAA-15, −18, −19, MetOp-A, -B). The double difference method was used to estimate and thus eliminate the inter-sensor bias, and a decadal diurnal correction was used to reduce the impact of different local equator crossing times on climate trends. The “no-rain” conditions were determined for AMSU-A data by channels 1 and 15, and for MWTS-2 data by channels 1 and 7. Finally, the decadal linear trends of atmospheric temperature from 1998 to 2020 were obtained after applying the inter-sensor bias calibration and inter-decadal diurnal correction to AMSU-A and MWTS-2 data from NOAA-15, −18, −19; MetOp-A, -B; and FY-3D. A warming trend was found in the AMSU-A window and tropospheric channels (1–9 and 15) and a cooling trend in stratospheric channels (10–14). The warming (cooling) trends of channels 7–9 (10) were relatively small. The warming (cooling) trends of AMSU-A channels 1–6 (14–15) were significantly reduced after the inter-decadal diurnal correction.

CERES Energy Balanced and Filled (EBAF) from Afternoon-Only Satellite Orbits

The Clouds and the Earth’s Radiant Energy System (CERES) Energy Balanced and Filled (EBAF) data product uses a diurnal correction methodology to produce a shortwave (SW) top-of-atmosphere (TOA) radiative flux time series that accounts for diurnal cycle changes between CERES observation times while ensuring that the stability of the EBAF record is tied as closely as possible to CERES instrument calibration stability. The current EBAF Ed4.1 data product combines observations from Terra and Aqua after July 2002. However, the Terra satellite will start to drift in Mean Local Time (MLT) in early 2021, and Aqua’s MLT will start to drift in 2022. To ensure the EBAF record remains temporally stable, we explore the feasibility of using only CERES instruments from afternoon satellite orbits with a tight 1330 MLT after July 2002. We test this approach by directly comparing SW TOA fluxes generated after applying diurnal corrections to Aqua-only and to Terra + Aqua for 07/2002–06/2019. We find that global climatological mean SW TOA fluxes for these two cases are within 0.01 Wm−2 and the trend of the difference is < is 0.03 Wm−2 per decade.

IDENTIFIKASI POLA SEBARAN INTRUSI BATUAN BAWAH PERMUKAAN MENGGUNAKAN METODE GEOMAGNET DI SUNGAI JENELATA KABUPATEN GOWA

AbstrakPenelitian ini dilakukan di Sungai Jenelata, Kabupaten Gowa, Sulawesi Selatan mengunakan metode geomagnet . Tujuan dari penelitian ini yaitu mengidentifikasi struktur geologi bawah permukaan pada daerah penelitian. Jumlah titik pengukuran sebanyak 248 dengan area seluas 70 × 300 meter. Akuisisi data dilakukan dengan menggunakan satu alat magnetometer. Sementara pengolahan data menggunakan koreksi harian dan koreksi IGRF serta filter upward continuation. Pemodelan dilakukan dengan metode forward modeling dengan menggunakan perangkat lunak Mag2DC. Medan magnetik total berkisar antara 42.456 sampai 43.111,6 nT. Berdasarkan interpretasi kualitatif pada kontur anomali magnetik lokal didapatkan variasi nilai anomali antara -320 sampai 240 nT. Sedangkan interpretasi kuantitatif menunjukkan adanya batuan basalt dengan nilai suseptibilitas sampai SI, yang menerobos batuan pyroclastic dengan nilai suseptibilitas hingga SI dalam dalam bentuk dyke. Kata Kunci: Geomagnet, dyke, Suseptibilitas, Sungai Jenelata.AbstractThis research has been conducted using geomagnetic method at Jenelata River, Gowa regency, South Sulawesi. The purpose of this study is to identify subsurface geological structure of the study area. The number of measurement points as much as 248 points with area 70 × 300 meters. The process of data acquisition using a magnetometer. Data processing was carried out with the diurnal correction and IGRF correction and using filter upward continuation. Modelling conducted using forward modeling using the software Mag2DC. The total magnetic field ranges from 42,456 to 43,111.6 nT. Based on a qualitative interpretation obtain local magnetic anomaly contour variations values between -320 to 240 nT. While the quantitative interpretation indicates basalt rocks with susceptibility values to SI, which breached pyroclastic rocks with susceptibility values to SI, in the form of dyke. Keywords: Geomagnetic, dyke, Susceptibility, Jenelata River

Removing Diurnal Cycle Contamination in Satellite-Derived Tropospheric Temperatures: Understanding Tropical Tropospheric Trend Discrepancies

Independent research teams have constructed long-term tropical time series of the temperature of the middle troposphere (TMT) using satellite Microwave Sounding Unit (MSU) and Advanced MSU (AMSU) measurements. Despite careful efforts to homogenize the MSU/AMSU measurements, tropical TMT trends beginning in 1979 disagree by more than a factor of 3. Previous studies suggest that the discrepancy in tropical TMT trends is caused by differences in both the NOAA-9 warm target factor and diurnal drift corrections. This work introduces a new observationally based method for removing biases related to satellite diurnal drift. Over land, the derived diurnal correction is similar to a general circulation model (GCM) diurnal cycle. Over ocean, the diurnal corrections have a negligible effect on TMT trends, indicating that oceanic biases are small. It is demonstrated that this method is effective at removing biases between coorbiting satellites and biases between nodes of individual satellites. Using a homogenized TMT dataset, the ratio of tropical tropospheric temperature trends relative to surface temperature trends is in accord with the ratio from GCMs. It is shown that bias corrections for diurnal drift based on a GCM produce tropical trends very similar to those from the observationally based correction, with a trend difference smaller than 0.02 K decade−1. Differences between various TMT datasets are explored further. Large differences in tropical TMT trends between this work and that of the University of Alabama in Huntsville (UAH) are attributed to differences in the treatment of the NOAA-9 target factor and the diurnal cycle correction.

PATMOS-x: Results from a Diurnally Corrected 30-yr Satellite Cloud Climatology

Satellite drift is a historical issue affecting the consistency of those few satellite records capable of being used for studies on climate time scales. Here, the authors address this issue for the Pathfinder Atmospheres Extended (PATMOS-x)/Advanced Very High Resolution Radiometer (AVHRR) cloudiness record, which spans three decades and 11 disparate sensors. A two-harmonic sinusoidal function is fit to a mean diurnal cycle of cloudiness derived over the course of the entire AVHRR record. The authors validate this function against measurements from Geostationary Operational Environmental Satellite (GOES) sensors, finding good agreement, and then test the stability of the diurnal cycle over the course of the AVHRR record. It is found that the diurnal cycle is subject to some interannual variability over land but that the differences are somewhat offset when averaged over an entire day. The fit function is used to generate daily averaged time series of ice, water, and total cloudiness over the tropics, where it is found that the diurnal correction affects the magnitude and even the sign of long-term cloudiness trends. A statistical method is applied to determine the minimum length of time required to detect significant trends, and the authors find that only recently have they begun generating satellite records of sufficient length to detect trends in cloudiness.