Search results for "Season"
showing 10 items of 1002 documents
Introducing the Time Series Change Visualization and Interpretation (TSCVI) method for the interpretation of global NDVI changes
2021
Abstract This paper presents a novel method for the visualization of changes in vegetation related variables. This method, termed Time Series Change Visualization and Interpretation (TSCVI), allows to summarize changes associated to both vegetation productivity and phenology in a single map. To that end, three metrics are retrieved on an annual basis from plotting NDVI (Normalized Difference Vegetation Index) values on a polar plot. Changes in these metrics are then analyzed and mapped in an IHS (Intensity Hue Saturation) image, where colors indicate changes regarding the growing-season (earlier or later occurrence, stronger or weaker seasonality), while changes associated to productivity a…
Has the Northern Hemisphere been warming or cooling during the boreal winter of the last few decades?
2013
Abstract The Intergovernmental Panel on Climate Change (IPCC) reported a significant rise of the global mean surface temperature over the last 100 years, with a rate of warming over the last few decades almost double that over the last 100 years. The rate of warming is higher at land surfaces over the Northern Hemisphere (NH), and particularly extreme warming is occurring over the Arctic. In spite of the global warming trend, some asymmetries have been observed. In a recent study, a widespread cooling over the NH during the boreal winter season was reported, although other previous studies observed a warming during this season. In this paper we report trends in winter air temperatures over …
The value of local climate and weather information: an economic valuation of the decentralised meteorological provision in Kenya
2020
The development of Sub-Saharan Africa will become increasingly constrained by the acute climate sensitivity of livelihood practices. Weather and climate services can improve climate risks to development by informing plans and decisions that ultimately reduce losses/maximize beneficial opportunities from climate variability and change. Yet, such services are typically highly aggregated, and notoriously difficult to communicate, especially to smallholder farmers and pastoralists where the need is greatest. Kenya Meteorological Department (KMD) are decentralizing service provision, and in so doing, offering disaggregated, contextualized, and more easily understandable localized weather and sea…
Interannual to decadal variability of summer sea surface temperature in the Sea of Okhotsk recorded in the shell growth history of Stimpson's hard cl…
2017
Abstract Sclerochronological and shell stable oxygen isotopic analyses were conducted on live-caught specimens of Stimpson's hard clams, Mercenaria stimpsoni , from the southern Sea of Okhotsk, off northern Hokkaido, Japan. In this region, the main growing season of this species during early ontogeny (below the age of 12 years) lasts from mid-spring to mid-fall at sea surface temperatures (SST) between approximately 10 and 22 °C. Growth cessation begins between late fall and early spring at SST, below approximately 6 °C; however, shell growth was largely limited to the summer season later in life. Counting of annual increments indicated that this species had a relatively long life span of u…
Characterizing land condition variability in Ferlo, Senegal (2001–2009) using multi-temporal 1-km Apparent Green Cover (AGC) SPOT Vegetation data
2011
Abstract The ecosystem state or ‘land condition’ can be characterized by a set of attributes, which show variations at different temporal scales. A multi-resolution analysis (MRA) based on the wavelet transform (WT) has been implemented to examine the land condition of a dryland region in Ferlo (Senegal) over the period 2001–2009. This methodology has proven to be useful for smoothing time series while considering those temporal resolutions that incorporate information about the vegetation dynamics. For this purpose, time series of the 1-km Apparent Green Cover (AGC) from the 10-day composites SPOT Vegetation (VGT) data are analyzed. Two relevant outputs from the MRA, A 1 (de-noised) and th…
The bivalve <i>Glycymeris planicostalis</i> as a high-resolution paleoclimate archive for the Rupelian (Early Oligocene) …
2015
Abstract. Current global warming is likely to result in a unipolar glaciated world with unpredictable repercussions on atmospheric and oceanic circulation patterns. These changes are expected to affect seasonal extremes and the year-to-year variability of seasonality. To better constrain the mode and tempo of the anticipated changes, climatologists require ultra-high-resolution proxy data of time intervals in the past, e.g., the Oligocene, during which boundary conditions were similar to those predicted for the near future. In the present paper, we assess whether such information can be obtained from shells of the long-lived bivalve mollusk Glycymeris planicostalis from the late Rupelian of…
A simple method to directly retrieve reference evapotranspiration from geostationary satellite images
2013
Abstract Application of FAO-56 methodology for the assessment of reference evapotranspiration, ET 0 , is challenging in areas of the world with sparse meteorological network stations. For this reason alternative procedures using remotely observed data have been proposed in the literature. In this work, a simplified version of the Makkink approach [J. Inst. Wat. Eng. 11: 277–288, 1957] was tested in a typical Mediterranean environment (Sicily, Italy). The implemented Makkink approach (MAK) uses remotely estimated solar radiation derived from Meteosat Second Generation (MSG) satellite data and in situ observations of air temperature to assess ET 0 at daily time scale. Alternatively, taking ad…
European phenological response to climate change matches the warming pattern
2006
Global climate change impacts can already be tracked in many physical and biological systems; in particular, terrestrial ecosystems provide a consistent picture of observed changes. One of the preferred indicators is phenology, the science of natural recurring events, as their recorded dates provide a high-temporal resolution of ongoing changes. Thus, numerous analyses have demonstrated an earlier onset of spring events for mid and higher latitudes and a lengthening of the growing season. However, published single-site or single-species studies are particularly open to suspicion of being biased towards predominantly reporting climate change-induced impacts. No comprehensive study or meta-an…
Sclerochronological evidence of pronounced seasonality from the late Pliocene of the southern North Sea basin and its implications
2022
Oxygen isotope (δ18O) sclerochronology of benthic marine molluscs provides a means of reconstructing the seasonal range in seafloor temperature, subject to use of an appropriate equation relating shell δ18O to temperature and water δ18O, a reasonably accurate estimation of water δ18O, and due consideration of growth-rate effects. Taking these factors into account, δ18O data from late Pliocene bivalves of the southern North Sea basin (Belgium and the Netherlands) indicate a seasonal seafloor range a little smaller than now in the area. Microgrowth-increment data from Aequipecten opercularis, together with the species composition of the bivalve assemblage and aspects of preservation, suggest …
Seabirds mated for life migrate separately to the same places: behavioural coordination or shared proximate causes?
2015
Long-term pair bonds occur in diverse animal taxa, but they are most common in birds, and can last from a few years to a lifetime. In many of these species, after the reproductive season, birds migrate to distant nonbreeding grounds where they remain for several months, and until recently, little was known about whether partners maintain contact during migration. This gap in knowledge was primarily due to past methodological difficulties in tracking long-term, large-scale movements of individuals. However, the development of new animal-borne geolocation devices has enabled researchers to track movements of individuals for a year or more. We tracked the annual migrations of both members of b…