Characterising electron butterfly pitch angle distributions in the magnetosphere through observations and simulations

The Imaging Electron Spectrometer (IES) on the Polar satellite has measured the average characteristics of the equatorial electron pitch angle distributions (PADs) in the midnight sector as a function of radial distance out to the 9 RE apogee of the Polar satellite. Depressions in the observed fluxes of electrons occur with pitch angles around 90° in the equatorial zone, while the more field-aligned electrons remain largely unchanged. The orbital precessions of the satellite have allowed much of the inner equatorial magnetosphere to be observed. Statistically, butterfly PADs with different shapes are observed selectively in different regions, which can provide insight to their source and possible history. Electron paths of varied pitch angles were modelled using Runge-Kutta approximations of the Lorentz force in a Tsyganenko (T96) simulated magnetosphere. The resulting drift paths suggest that the process of magnetopause shadowing plays a significant role in the loss of these electrons. Case studies of the drifting patterns of electrons with varied pitch angles were simulated from Polar's orbit when a butterfly PAD was observed on 3 October 2002 at an altitude near 9 RE and on 12 September 2000 at an altitude near 6 RE. These two locations represent regions on each side of the boundary of stable trapping. The modelling effort strongly suggests that magnetopause shadowing does play a significant role in the loss of equatorially drifting electrons from the outer regions of the inner magnetosphere

PRE-FAILURE PERSISTENT SCATTERER INTERFEROMETRY (PSI) AND SOIL MOISTURE INDEX (SMI) ANALYSIS OF THE EDENVILLE DAM IN MIDLAND, MICHIGAN

The Edenville Dam was an earth dam located approximately 15 miles northwest of Midland, Michigan. The dam impounded the Tobacco and Tittabawassee Rivers, forming Wixom Lake. On May 19th, 2020, the dam failed after three days of elevated rainfall. Flood waters from Wixom Lake caused the overtopping of the Sanford Dam downstream, and the flooding of the surrounding area. The Edenville Dam was 95 years old at the time of failure and was constructed before modern geotechnical engineering methods were widely practiced. Dam infrastructure similar to Edenville is not uncommon, requiring the need for increased monitoring. A pre-failure analysis was conducted to show the application of remote sensing in dam monitoring. A Persistent Scatterer Interferometry (PSI), a form of synthetic aperture radar (SAR), analysis of 25 Sentinel-1 images was used to measure line-of-sight displacement 15 months prior to the failure. A Soil Moisture Index (SMI) analysis of 14 Landsat-8 images were used to observe relative moisture content between 2016 and 2020. The PSI analysis showed stable embankments along the dam had velocities ranging from 0 to -5 mm/yr. A localized area of negative displacement with a velocity of -20 mm/yr, was observed approximately 30 m north of the failure location. Displacement was not observed within the approximate failure location, suggesting movement did not occur in the 15 months prior, or rapid deformation (\u3e 30 mm/yr) occurred resulting in the decorrelation of the SAR signal. The SMI analysis showed the Edenville Dam exhibited no long-term change (increase or decrease) in relative soil moisture content from 2016 to 2020. The study illustrates the benefits and limitations of the PSI and SMI analysis in the Edenville example and makes recommendations for future monitoring/analysis work

PENERAPAN K-MEANS CLUSTERING UNTUK MENGETAHUI VARIETAS PADI UNGGUL PRODUKSI BALAI PENGKAJIAN TEKNOLOGI PERTANIAN JAWA TIMUR

ABSTRAK Banyaknya varietas padi unggul dalam riwayat pertanian Indonesia adalah suatu keuntungan tersendiri bagi masyarakat maupun pemerintah. Pasalnya, fokus penanaman varietas unggul mampu meningkatkan hasil dan kualitas pertanian padi yang merupakan sumber pangan utama bersektor tanam terluas di Indonesia. Akan tetapi, keanekaragaman varietas padi unggul mampu menimbulkan masalah di bidang penelitian yang bertujuan menciptakan varietas-varietas unggul baru lainnya apabila kurang adanya informasi yang memadai. Dalam proses penelitian, produksi maupun distribusi, pihak Unit Pengelola Benih Sumber BPTP masih memanfaatkan pencatatan manual pada buku maupun nota-nota. Padahal, hingga saat ini saja tercatat 37 varietas Inpari, 19 varietas Hipa, 10 varietas Inpago dan 9 varietas Inpara sebagai varietas unggul baru, belum termasuk varietas unggul sebelumnya. Petugas akan kesulitan dalam melakukan pendataan dikarenakan faktor waktu, dana dan keakuratan data sehingga pemilihan kelompok varietas unggul padi yang akan diteliti atau diproduksi dipilih secara subyektif. Oleh karena itu untuk mempermudah pengelompokan varietas unggul padi, penulis membangun sebuah sistem pendukung keputusan memanfaatkan metode K-Means Clustering. Data-data padi dikelompokan ke dalam 3 cluster yaitu unggul, sedang dan kurang, serta dikelompokan berdasarkan kriteria -kriteria padi unggul yaitu umur, tingkat rontok, kadar amilosa, berat butit dan rata hasil panen. Sistem ini dibangun menggunakan software Microsoft Visual Studio 2010 dan Microsoft SQL Server 2008. Hasil pengujian metode K-Means Clustering mendapatkan hasil bahwa perhitungan manual dengan sistem memiliki kesesuaian sebesar 100%, sedangkan pengujian metode dari sistem dengan data pakar memiliki keakuratan sebesar 92.54%. Dari pengujian fungsionalitas sistem dengan operating system yang berbeda yaitu Windows 7 Professional, Windows 8.1 dan Windows 10, didapatkan hasil sistem dapat berjalan 100% sesuai dengan fungsinya. Sedangkan hasil pengujian user dari 13 koresponden menunjukan bahwa 83.1% sistem berjalan dengan baik dan 16.9% sisanya memiliki nilai cukup. Kata kunci : Sistem Pendukung Keputusan (SPK), Pengelompokan Varietas Padi Unggul, K-Means Clustering, BPTP Jawa Timu

Energetic particle sounding of the magnetospheric cusp with ISEE-1

Observations on 30 October 1978 show the ISEE-1 spacecraft passing though the high-altitude dayside northern magnetospheric cusp region from roughly 16:00 to 18:30 UT, during a slow solar wind period (~380 km/s). More than two orders of magnitude enhancements of the cusp energetic particle (CEP) fluxes were observed along with a depressed and turbulent local magnetic field. The observed variations of the pitch angle distributions (PAD) provide a unique opportunity to determine the structure of the cusp and the origin of the CEP. Through a boundary sounding technique, the location and orientation of the cusp poleward (or backside) boundary was observed for almost 10 min during which time it appeared initially to be stationary in the GSM/GSE X-direction and then moved sunward about 0.12 Earth radii (RE). The orientation remained approximately perpendicular to the GSM/GSE X-axis until it was observed to rotate by 60 degrees in ~3 min before ISEE-1 was fully inside the cusp cavity. The cavity itself was filled with CEP fluxes displaying large anisotropies, indicative of their source being located below (Earthward) of the satellite location. The spacecraft entered from the backside of the cusp, then traveled ~4 RE through the cavity, and exited through the "top" of the cavity leaving a region of energetic ions below. The PADs demonstrate that the bow shock cannot be the main source of the observed CEPs. The CEP fluxes were measured at about 8.5 h MLT when the IMF had both an 8–10 nT duskward and southward component