Kenji Yoshikawa

Kenji Yoshikawa
University of Alaska Fairbanks · Water and Environmental Research Center (WERC)

About

86
Publications
16,356
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4,349
Citations
Citations since 2016
4 Research Items
1799 Citations
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2016201720182019202020212022050100150200250300
2016201720182019202020212022050100150200250300
Introduction
Skills and Expertise

Publications

Publications (86)
Article
Food cellars, otherwise referred to as ice or meat cellars, (lednik in Russian, k’aetyran in Chukchi, siġļuaq in Iñupiaq, and siqlugaq in Yupik) are a natural form of refrigeration in permafrost or seasonally frozen ground used to preserve, age, and ferment foods harvested for subsistence, including marine mammals, birds, fish, and plants. Indigeno...
Article
Full-text available
Tropical mountain permafrost has a unique thermal regime due to ground surface exposure to strong solar radiation. The intensity of the surface offset resulting from snow cover also strongly affects the absence or presence of permafrost. Latent heat transfer and reflected solar radiation (higher albedo) that occur during the snow-covered season con...
Article
Full-text available
Ice cellars are a natural form of refrigeration constructed within permafrost. They are traditionally employed by indigenous Arctic peoples to store harvested wildlife. Recent reports from Alaska indicate that ice cellars are “failing” through mechanisms that include flooding and collapse, which are often attributed to climate change. In cooperatio...
Conference Paper
Integrated science, technology, engineering and math (STEM) solutions and effective, relevant learning processes are required to address the challenges that a changing climate presents to many Arctic communities. Learning that can both enhance a community’s understanding and generate new knowledge about climate change and it’s impacts at both local...
Article
High-resolution maps of potential frozen ground distribution in South America have been produced for the present day (0ka) and the Last Glacial Maximum (21ka). Surface air temperature outputs from global climate models (GCMs) of the recent Paleoclimate Model Intercomparison Project were used for the reconstructions, and then downscaled from regiona...
Conference Paper
Full-text available
Permafrost underlies all areas of the North Slope of Alaska except beneath some deep lakes and river channels. Of the 100+ monitoring sites, the majority of permafrost sites were established during or since the 1980s, and most active-layer sites date from the early to mid-1990s. All of these long-term sites contribute to the Global Terrestrial Netw...
Article
A high-resolution map of potential frozen ground distribution in NE Asia (90–150°E, 25–60°N) at the period of the Last Permafrost Maximum (LPM, c. 21 000 years ago) was dually reconstructed by means of a statistical classification using air freezing and thawing indices and a topographical downscaling using a digital relief model (ETOPO1). Backgroun...
Article
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Here, global-scale frozen ground distribution from the Last Glacial Maximum (LGM) has been reconstructed using multi-model ensembles of global climate models, and then compared with evidence-based knowledge and earlier numerical results. Modeled soil temperatures, taken from Paleoclimate Modelling Intercomparison Project phase III (PMIP3) simulatio...
Article
Full-text available
Global-scale frozen ground distribution during the Last Glacial Maximum (LGM) was reconstructed using multi-model ensembles of global climate models, and then compared with evidence-based knowledge and earlier numerical results. Modeled soil temperatures, taken from Paleoclimate Modelling Intercomparison Project Phase III (PMIP3) simulations, were...
Conference Paper
Radar detection of substantial presence of mid-latitude subsurface ice on Mars has been subject to a wide debate and uncertain observations. More often ice dielectric signature as induced from the inversion of the real part of the dielectric constant (e.g. ε = 3) can be confused with other silicate rich materials that have close values such loose d...
Article
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A snapshot of the thermal state of permafrost in northern North America during the International Polar Year (IPY) was developed using ground temperature data collected from 350 boreholes. More than half these were established during IPY to enhance the network in sparsely monitored regions. The measurement sites span a diverse range of ecoclimatic a...
Article
Radar detection of subsurface ice on Mars has been widely debated in part because the dielectric signature of ice, as deduced from the dielectric constant, can be confused with dry-silicate-rich materials. To identify the ice dielectric signature, it is crucial to estimate the imaginary part of the dielectric permittivity inferred from the dielectr...
Article
The lenses of perennially overcooled water brines (cryopegs) derived from ancient marine sedi-ments and sandwiched within permafrost 10 to 120,000 years ago after the placeArctic Ocean regressions. In these lenses freezing is prevented by freezing-point depression due to the dis-solved salt and they remain liquid at the in situ temperatures down to...
Article
Subsurface water on Mars has been subject to several hypothesis and debates. To access its potential distribution and state in the fractured Martian subsurface, two low-frequency radar sounders (MARSIS and SHARAD) are currently probing the Martian upper crust exploring dielectric evidence of volatiles presence. The identification of volatiles signa...
Article
Full-text available
The permafrost distribution under Quaternary climate conditions is investigated by a frozen ground classification method (Left figure) based solely upon the near surface air thermal indices as a diagnosing analysis of the Paleoclimate Model Intercomparison Project 2 (PMIP2) output. The methodology is constructed using the present-day distribution o...
Article
Recent observations indicate a warming of permafrost in many northern and mountain regions with a resulting degradation of ice-rich and carbon-rich permafrost. Permafrost temperature has increased by 1 to 2°C in northern Russia during the last 30 to 35 years. This observed increase is very similar to what has been observed in Alaska where the detai...
Article
Landscape modifications in Arctic and subarctic regions due to warming climate conditions have been reported in recent years. This work describes the rapid development of a thermokarst in Interior Alaska over a two-year period. The research was conducted in the Caribou-Poker Creeks Research Watershed, the only research watershed in the United State...
Conference Paper
Full-text available
A new permafrost map of Alaska (see inside of front cover), using a terrain-unit approach for mapping permafrost distribution based on climate and surficial geology, is presented. This map represents the third iteration of a permafrost map for Alaska, following the circum-Arctic permafrost map (Brown et al. 1997), which made minor modifications to...
Article
The goal of this study was to gain a better understanding of the hydrology of a permafrost affected watershed using analyses of DOC. DOC from water samples collected in the Caribou–Poker Creeks Research Watershed (CPCRW) was analyzed by several techniques, including pyrolysis-gas chromatography/mass spectrometry (py-GC/MS). Results showed that the...
Article
Full-text available
The Fairbanks Permafrost Experimental Station was established in 1945 near Fairbanks, Alaska. In 1946 vegetation was removed from two plots (the Linell plots) to investigate the impacts of vegetation disturbance on permafrost degradation. We revisited the sites in 2007 to evaluate the permafrost table using probes and direct current electrical resi...
Article
The objective of this project is to establish long-term permafrost monitoring sites adjacent to schools along the circum polar permafrost region. Permafrost will be one of the important indicators for monitoring climatic change in the future. Change in permafrost conditions also affects local ecosystems, hydrological regimes and natural disasters....
Article
Full-text available
Author Posting. © American Geophysical Union, 2007. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 112 (2007): G04S54, doi:10.1029/2006JG000353. Dramatic changes have been observed in the Arctic over the last ce...
Article
Subsurface hydrology is one of the most important components of earth science. Of particular interest is the impact of a changing climate on Arctic hydrology and the concurrent degradation of permafrost. The presence or absence of permafrost plays a significant role in balancing the infiltration process between surface water and groundwater. These...
Article
The purpose of this study is to identify and characterize groundwater infiltration and discharge processes in continuous permafrost regions between the Lena River in Siberia and the Mackenzie River in Canada. The source and heat content of the intra-, or sub- permafrost groundwater is being studied. Intra permafrost (30- 40m below ground surface) t...
Article
On the mountain of Denali, Alaska (also known as Mt. McKinley), weathering processes are dominated by secondary crystallization (calcite) and oxidation (varnish), but frost action is limited. During the summer of 2002-2003, two study sites (a north-facing rock wall and a south-facing rock wall) on Denali showed limited numbers of effective freeze-t...
Article
The purpose of this study was to better understand the link between dissolved organic matter (DOM) in soil leachates and the different vegetation cover types in a boreal forest. Soil cores were collected from the Caribou Poker Creeks Research Watershed (CPCRW) and subjected to a laboratory leaching procedure. The leachates were subjected to a numbe...
Article
Full-text available
1] Six different geophysical investigations, (1) ground-penetrating radar, (2) DC resistivity sounding, (3) seismic refraction, (4) very low frequency (VHF) electromagnetic, (5) helicopter borne electromagnetic (HEM), and (6) transient electromagnetic (TEM) techniques, were employed to obtain information on the ice body properties of pingos near Fa...
Article
Permafrost exerts critical controls upon hydrological, biological and ecological processes. As permafrost becomes thinner, small springs can penetrate the frozen ground and lead to formation of aufeis in the winter and more stable baseflow in the summer. As permafrost degrades to the point of becoming discontinuous, surface water can infiltrate to...
Conference Paper
Full-text available
A warmer climate in the arctic region is shown to increase the frequency and severity of fires. An investigation of the effects of a fire on a tundra environment can result in a better understanding of the impact a warming climate and its secondary effects on the arctic ecosystem and its morphology, where the presence of permafrost is of vital impo...
Article
During the summer of 2004, the Geophysical Institute University of Alaska Fairbanks (GI UAF) established the Gakona Permafrost Observatory. This project is funded by the Office of Naval Research and the National Science Foundation. The Observatory is located in a large intermountain depression in the Copper River Basin. Permafrost in this area is w...
Article
In the last 50 years a wide range of changes in the Arctic related to hydrology have been detected. Many of these changes were documented since the mid-1970s; however it is quite likely change initiated early in the 20th century prior to extensive observational records in arctic regions. Some of the changes, like later freeze-up and earlier break-u...
Article
In an ongoing study of the rapidly evolving thermokarst located in the Caribou-Poker Creeks Research Watershed - Alaska, a number of geomorphologic changes were observed during the 2004 and 2005 field studies. Evidence of a talik formation at the active layer-permafrost boundary, achieved by a GPR survey conducted in March 2005, is indicative of a...
Article
Full-text available
Permafrost extent has been estimated using an equivalent latitude / elevation model based upon good climate, terrain and soil property data. This research extends a previously developed model to a relatively data sparse region. We are applying the general equivalent attitude model developed for Caribou-Poker Creeks Research Watershed over the much...
Article
Full-text available
The Arctic climate is changing. Permafrost is warming, hydrological processes are changing and biological and social systems are also evolving in response to these changing conditions. Knowing how the structure and function of arctic terrestrial ecosystems are responding to recent and persistent climate change is paramount to understanding the futu...
Conference Paper
Dissolved organic matter (DOM) is present in nearly all surface waters and many groundwaters used for domestic water supplies. The standard analyses for organic matter in water, DOM and color, provide very little information about the character of the organic matter, or its potential to serve as a disinfection by-product (DBP) precursor, biological...
Conference Paper
The primary control on local hydrological processes in northern regions is dictated by the presence or absence of permafrost, but is also influenced by the thickness of the active layer and the total thickness of the underlying permafrost. As permafrost becomes thinner or decreases in areal extent, the interaction of surface and subpermafrost groun...
Conference Paper
Several landscape modifications are indicative of a warming climate in Arctic arid Sub-arctic regions. Preliminary results of detailed analyses on the development of a thermokarst are presented here. Thermokarst occur when massive ice buried in permafrost thaws allowing the surface to rapidly subside. Although thermokarst is a natural process that...
Article
The rapid thermokarst development in the Caribou Poker Creeks Research Watershed is a relatively new feature in this predominantly discontinuous permafrost region. The thermokarst was initiated by permafrost degradation and precipitated primarily by the rain event that occurred in July 2003. Initial results of a field study on the thermokarst evolu...
Article
Full-text available
It has been suggested that methane clathrate is stable in the subsurface of Mars (Max and Cliiord, (J. Geophys. Res.-Planets 105 (E2) (2000) 4165). Max and Cliiord (Geophys. Res. Lett. 28(9) (2001) 1787) have proposed that the Martian chaotic terrain could be a surface manifestation of the dissociation of subsurface methane clathrate hydrate. They...
Article
This paper describes four recent applications of analytical pyrolysis in environmental science and engineering. In all applications, samples were analyzed in order to provide information about the origin of organic matter or changes to an organic matrix. In the first application, pyrolysis-gas chromatography/mass spectrometry (GC/MS) and pyrolysis-...
Article
The objective of this paper is to review research conducted over the past decade on the application of multi-temporal remote sensing for monitoring changes of Arctic tundra lands. Emphasis is placed on results from the National Science Foundation Land–Air–Ice Interactions (LAII) program and on optical remote sensing techniques. Case studies demonst...
Article
More than 30,000 liters/sec. of spring water discharges along the eastern part of foothills of the Brooks Range, North Slope, Alaska. These springs flow all year around and cover wide areas with aufeis every winter. In Arctic regions, aufeis is among the biggest temporary storage of freshwater during winter period (more than 8 months). This study e...
Article
The weathering of granodiorite porphyry is examined in the extremely cold and dry environment of the inland part of Antarctica. Weathering features include granular disintegration, rock varnish, and sheeting. Sheeting has gradually proceeded since the exposing of the nunatak, but the other types of weathering have not actively advanced in recent ti...
Article
In the past 30 years, the earth's northern climate has warmed appreciably. Mounting evidence suggests that climate warming is being amplified at the earth's polar regions. A warmer northern climate could lead to the gradual loss of circumpolar permafrost. Northern soils are estimated to contain 25-33% of the world's soil carbon, much of which is fr...
Article
Although white spruce has advanced into tundra ecosystems throughout Alaska since the late 1800s, presumably in response to a regional increase in temperature, there is high variance in the magnitude of change in treeline position among arctic treeline sites. We investigated the role of permafrost as a modulator of vegetation response to climate by...
Article
We seek correlations between measurements made by a variety of soil bulk-dielectric measurement devices in the two dominant moss types of Alaska's North Slope. In permafrost regions, the soil moisture content of the shallow subsurface exerts a critical control over the thermal properties regime of the deeper subsurface. The dynamics of land cover c...
Article
The broadest impacts of climate change to the terrestrial arctic regions will result through consequent effects of changing permafrost structure and extent. As the climate differentially warms in summer and winter, the permafrost will become warmer, the active layer (the layer of soil above the permafrost that annually experiences freeze and thaw)...
Article
The purpose of this study was to characterize the geomorphological processes controlling the dynamics of ponds and to identify and characterize groundwater infiltration and surface water dynamics for a tundra terrain located in discontinuous permafrost near Council, Alaska. Thermokarst processes and permafrost degradation were studied, focusing upo...
Article
Permafrost degradation leads to substantial changes in soil thermal and hydrologic characteristics. We investigated the effects of changes in active layer thickness and soil drainage on vegetation distribution near the arctic treeline on the Seward Peninsula, Alaska. We measured active layer thickness, soil moisture, density of tall shrub species,...
Article
We developed a wideband, low-power, lightweight, prototype ground-penetrating radar (GPR) for subsurface exploration for Mars. The transmitter and receiver subsystems were constructed using a commercially available radio frequency (RF) and digital integrated circuits, connectorized components, and evaluation boards. The transmit/receive system, ant...
Article
Permafrost has received much attention recently because surface temperatures are rising in most permafrost areas of the Earth, bringing permafrost to the edge of widespread thawing and degradation. The thawing of permafrost that already occurs at the southern limits of the permafrost zone can generate dramatic changes in ecosystems and in infrastru...
Article
Preliminary analyses have revealed that many ponds near Council, Alaska on the Seward Peninsula are shrinking when compared with aerial photographs taken over the last 50 years. It is important to investigate the cause of this change to determine if this could be a broad scale result of a changing climate. To better understand the loss mechanisms c...
Article
Although annual precipitation (~250-300 mm) on the North Slope of Alaska would place this area in a semi-arid classification, significant individual events occur. For example, in July 1999 over 100 mm of rain fell during a 50-hour period and in August 2002 over 60 mm fell in a 20-hour period. These major events are of great importance as they often...
Article
The objective is to detect the hydrological and cryological structure of the cold continuous permafrost subsurface using geophysical methods. We believe that a lot of water potentially exists as solid and liquid phases underground on Mars. It is likely that the liquid fluid would be high in saline concentration (brine). The ground freezing process...
Article
The soil moisture regime in the sub-arctic environment plays an important role in a number of processes related to climate change including soil respiration, permafrost distribution, and the frequency and severity of wildfires. In order to understand and predict ecosystem response to a changing climate and resulting feedbacks, it is critical to qua...
Article
A realistic way to establish long-term permafrost temperature records is to reoccupy the sites where high quality permafrost temperature records were obtained for some period of time in the past. One such ideal place is Barrow, Alaska. During the past year a Permafrost Observatory was established at Barrow. The overall goal of the project is to est...
Article
Full-text available
Permafrost is an important control over the distribution of major vegetation types in the low arctic, and temporal changes in permafrost extent may thus be tightly coupled to changes in plant community distribution. For example, spruce trees have become more widespread during the 20th century on the Seward Peninsula, but in permafrost-affected area...