Agricultural cropland extent and areas of South Asia derived using Landsat satellite 30-m time-series big-data using random forest machine learning algorithms on the Google Earth Engine cloud

ABSTRACT

The South Asia (India, Pakistan, Bangladesh, Nepal, Sri Lanka and Bhutan) has a staggering 900 million people (~43% of the population) who face food insecurity or severe food insecurity as per United Nations, Food and Agriculture Organization’s (FAO) the Food Insecurity Experience Scale (FIES). The existing coarse-resolution (≥250-m) cropland maps lack precision in geo-location of individual farms and have low map accuracies. This also results in uncertainties in cropland areas calculated from such products. Thereby, the overarching goal of this study was to develop a high spatial resolution (30-m or better) baseline cropland extent product of South Asia for the year 2015 using Landsat satellite time-series big-data and machine learning algorithms (MLAs) on the Google Earth Engine (GEE) cloud computing platform. To eliminate the impact of clouds, 10 time-composited Landsat bands (blue, green, red, NIR, SWIR1, SWIR2, Thermal, EVI, NDVI, NDWI) were derived for each of the three time-periods over 12 months (monsoon: Days of the Year (DOY) 151–300; winter: DOY 301–365 plus 1–60; and summer: DOY 61–150), taking the every 8-day data from Landsat-8 and 7 for the years 2013–2015, for a total of 30-bands plus global digital elevation model (GDEM) derived slope band. This 31-band mega-file big data-cube was composed for each of the five agro-ecological zones (AEZ’s) of South Asia and formed a baseline data for image classification and analysis. Knowledge-base for the Random Forest (RF) MLAs were developed using spatially well spread-out reference training data (N = 2179) in five AEZs. The classification was performed on GEE for each of the five AEZs using well-established knowledge-base and RF MLAs on the cloud. Map accuracies were measured using independent validation data (N = 1185). The survey showed that the South Asia cropland product had a producer’s accuracy of 89.9% (errors of omissions of 10.1%), user’s accuracy of 95.3% (errors of commission of 4.7%) and an overall accuracy of 88.7%. The National and sub-national (districts) areas computed from this cropland extent product explained 80-96% variability when compared with the National statistics of the South Asian Countries. The full-resolution imagery can be viewed at full-resolution, by zooming-in to any location in South Asia or the world, at www.croplands.org and the cropland products of South Asia downloaded from The Land Processes Distributed Active Archive Center (LP DAAC) of National Aeronautics and Space Administration (NASA) and the United States Geological Survey (USGS): https://lpdaac.usgs.gov/products/gfsad30saafgircev001/.     

Isotopic evolution of common lead

The isotopic composition of lead from galenas and feldspars of granitic rocks covering a time span of 3600 m.y. is reviewed. Hew data are combined with data from the literature, all ratios being normalized to a fixed value for the isotopic composition of lead in an inter-laboratory reference sample. Comparison of feldspar and galena results show that the isotopic composition of initial lead in granitic rocks may be identical to, or more radiogenic than, that in coeval stratiform (or ‘single stage’) ore deposits. The isotopic evolution of terrestrial lead over the past 3600 m.y. deduced from the stratiform ore data does not fit the closed system source. The data are best fitted to evolution models in which the value of μ (U²³⁸/Pb²⁰⁴ normalized to the present day) in the source has increased either over approximately the past 3.6 billion years or since the time of formation of the Earth. A limited number of high precision data for strontium likewise indicate open system isotopic evolution. In this system the Rb/Sr ratio appears to have decreased as a function of time. Physical models that explain the data are presented. Either mantle differentiation or crustal contamination processes could account for the change in μ in the source for the lead. The strontium data and some detailed studies of the isotopic composition of lead in oceanic volcanic rocks support mantle differentiation rather than crustal contamination. The exact nature of the mantle differentiation process cannot be specified, although empirical data favoring the existence of such a process are given. The best estimate of the age of the Earth, calculated with the data from 2750 and 3290 m.y.-old lead ores, is 4660 m.y.     

On the estimation of potential evaporation by the combination approach

Summary An evaluation of the combination approach of Penman [1] as modified by Kohler and Parmele [2] for estimating potential evaporation (PE) is made at Poona, India, vis-a-vis the evaporation from the Russian 20 m² tank and associated meteorological data. The use of Penman's form of wind function and net radiation computed from solar radiation, air temperature, and pyrgeometric value of sky radiation at 20.30 hrs. Indian Standard Time is seen to be adequate for obtaining reliable values of potential evaporation. Further lines of work to evaluate the potential evaporation climate over India are indicated.

---

Abschätzung der potentiellen Verdunstung durch kombinierte Annäherung

Zusammenfassung Eine Abschätzung der potentiellen Verdunstung (PE) wurde unter Benützung der Formel von Penman [1] mit der Abänderung von Kohler und Parmele [2] in Poona (Indien) durchgeführt und mit der Verdunstung von einer russischen 20m²-Wanne und gleichzeitigen meteorologischen Bedingungen verglichen. Die Benützung der Penman-Formel der Windabhängigkeit und der Strahlungsbilanz, berechnet aus Globalstrahlung, langwelliger Himmelsstrahlung und Lufttemperatur um 20.30 Uhr (indischer Lokalzeit) erweist sich als geeignet zur Gewinnung zuverlässiger Werte der potentiellen Verdunstung. Auf weitere Gesichtspunkte zur Bestimmung des potentiellen Verdunstungsklimas über Indien wird hingewiesen.

---

L'estimation de l'évaporation potentielle par combinaison approchée

Résumé L'évaluation du rapprochement de combinaison de Penman [1] telle qúelle est modifée par Kohler et Parmele [2] pour evaluér l'évaporation potentielle (PE) a étè employée à Poona, l'Inde, en comparaison avec l'évaporation de la citerne russe de 20 m² et des données météorologiques supplémentaires. L'emploi de la formule de Penman de l'effet du vent et de la radiation nette calculée de la radiation solaire, de la température de l'air et de la valeur pyrgéométrique de la radiation du ciel à 20 heures 30 (heure indienne) se trouve être suffisant pour obtenir les valeurs sûres de l'évaporation potentielle. De plus, des directives du travail pour évaluer l'évaporation potentielle au-dessus de l'Inde sont discutées.

     

Petrology of the dyke rocks of the western portions of Rajpipla hills,Broach district,Gujarat, India

The paper embodies the field, petrographic and petrochemical studies of the dykes occuring within the Deccan basalts, in the Western portions of Rajpipla hills. Major and minor dykes with different trends occur in the area varying in thickness from 2′ to 75′ and traceable lengthwise from few to several miles. The density of the dyke distribution is two per mile. The composition of the minor dykes ranges from teschenite to trachyte with dominant basaltic types and they seem to be coeval with the flows of the area. The major dolerite dykes are found to be post-lava. Both alkali-olivine basalt and tholeiitic types occur. The former phase preceeds the latter and includes the minor alkaline dykes. A differentiation trend based on new chemical analyses is proposed.     

The lateritic iron ores,itabiritic quartzites and epidiorites of the Kemmangundi area,Bababudan hills,Mysore state,India

Epidiorites forming the basement and occurring also as bands in ferruginous quartzites in Kemmangundi in the Bababudan Hills of Mysore State are described in regard to their structure, mineralogy, petrography, and the petrochemistry of the epidiorites and their role in the formation of the two types of iron ores in the area. The ferruginous quartzites, itabiritic iron ores, and epidiorites strike NW-SE and were simultaneously structurally deformed. They may be considered as eugeosynclinal formations. The data collected do not suggest any genetic relation between the itabiritic ores and the epidiorites. The lateritic iron ores on the other hand, were formed by the alteration of the ferruginous quartzites (itabiritic ores).

---

Zusammenfassung Itabiritische Quarzite und Epidiorite aus Kemmangundi in den Bababudan-Hügeln des Staates Mysore wurden hinsichtlich ihrer Struktur, ihres Mineralbestandes und ihrer chemischen Zusammensetzung untersucht. Insbesondere wird der Zusammenhang mit den beiden Typen von Eisenlagerstätten in der Gegend beleuchtet: Die itabiritischen Quarzite haben sich nicht aus den Epidioriten gebildet; dagegen sind die lateritischen Eisenerze als Verwitterungsprodukte der Eisenquarzite zu betrachten.

     

Environmental aspects in Dalli-Rajhara iron ore mine area,M.P. using digital image processing techniques

Landsat MSS (1982) and IRS LISS-II (1989) data have been used to study the land use/land cover changes in Dalli-Rajhara iron ore mine area. Supervised classification has been performed on the temporal data to generate land use/land cover maps. Land use/land cover categories generated from IRS LISS-II data of 36 m resolution has been resampled to 80 m and areal statistics have been computed for 2, 4, 8 and 10 km wide strips around Dalli-Rajhara iron ore mine. The environmental impact due to on-going mining activities in the area has been analysed. The results of this study indicate that due to increase in mine-related and agricultural activities, forests have been degraded and also forest areas have been reduced considerably.     

Quantitative precipitation forecasting over Narmada Catchment

Quantitative precipitation forecasting (QPF) has been attempted over the Narmada Catchment following a statistical approach. The catchment has been divided into five sub-regions for the development of QPF models with a maximum lead-time of 24 hours. For this purpose the data of daily rainfall from 56 raingauge stations, twice daily observations on different surface meteorological parameters from 28 meteorological observatories and upper air data from 11 aerological stations for the nine monsoon seasons of 1972–1980 have been utilized. The horizontal divergence, relative vorticity, vertical velocity and moisture divergence are computed using the kinematic method at different pressure levels and used as independent variables along with the rainfall and surface meteorological parameters. Multiple linear regression equations have been developed using the stepwise procedure separately with actual and square root and log-transformed rainfall using 8-year data (1972–1979). When these equations were verified with an independent data for the monsoon season of 1980, it was found that the transformed rainfall equations fared much better compared to the actual rainfall equations. The performance of the forecasts of QPF model compared to the climatological and persistence forecasts has been assessed by computing the verification scores using the forecasts for the monsoon season of 1980.     

Late Quaternary faunal change in coastal Arabian sea sediments

Carbonate content and faunal composition of two gravity cores from the coastal Arabian sea provide evidence of a major environmental change in surface ocean waters about 13,000 yr B.P. Radiocarbon dating indicates that deposition rates ranged from 1.8 to 9.8 cm/10³ yr, with a major change in rate occurring in one core at about 7500 yr B.P.     

Aseismic strength of kolkewadi dam

Kolkewadi Dam, a masonry gravity dam in India, is under construction at a'site which was considered to be non-seismic at the time of planning and design. Subsequently, some major and minor earthquake shocks have occurred in the area. In view of the earthquake activity in the region, it was necessary to estimate the seismic resistance of the dam. A dynamic analysis of the two highest monoliths of the dam has been carried out, based on the probable ground motion expected at the site, including a simplified analysis, treating the dam as a cantilever beam and a detailed analysis considering two-dimensional behaviour by the finite element method. It is concluded that the dam will be able to safely withstand the severest shock that has occurred in the region. The behaviour of models of one monolith has also been studied experimentally using a shake table. The experimental behaviour of the models compares favourably with the behaviour obtained theoretically, indicating the applicability of the theoretical method of analysis.