scholarly journals Snowfall in the Northern Great Lakes: Lessons Learned from a Multi-Sensor Observatory

2021 ◽  
pp. 1-61
Author(s):  
Mark S. Kulie ◽  
Claire Pettersen ◽  
Aronne J. Merrelli ◽  
Timothy J. Wagner ◽  
Norman B. Wood ◽  
...  
Keyword(s):  
Great Lakes ◽  
Lessons Learned ◽  
Great Lakes Region ◽  
Near Surface ◽  
Shallow Clouds ◽  
In Situ Observations ◽  
Snow Particle

BAMS Capsule:Profiling radar and ground-based in situ observations reveal the ubiquity of snowfall produced by shallow clouds, the importance of near-surface snowfall enhancement processes, and regime-dependent snow particle microphysical variability in the Northern Great Lakes Region.

scholarly journals The impact of near-surface soil moisture assimilation at subseasonal, seasonal, and inter-annual timescales

2015 ◽  
Vol 19 (12) ◽  
pp. 4831-4844 ◽  
Author(s):  
C. Draper ◽  
R. Reichle
Keyword(s):  
Soil Moisture ◽  
Data Assimilation ◽  
Surface Soil ◽  
Root Zone ◽  
Surface Model ◽  
Surface Soil Moisture ◽  
Near Surface ◽  
In Situ Observations ◽  
The Impact

Abstract. A 9 year record of Advanced Microwave Scanning Radiometer – Earth Observing System (AMSR-E) soil moisture retrievals are assimilated into the Catchment land surface model at four locations in the US. The assimilation is evaluated using the unbiased mean square error (ubMSE) relative to watershed-scale in situ observations, with the ubMSE separated into contributions from the subseasonal (SMshort), mean seasonal (SMseas), and inter-annual (SMlong) soil moisture dynamics. For near-surface soil moisture, the average ubMSE for Catchment without assimilation was (1.8 × 10−3 m3 m−3)2, of which 19 % was in SMlong, 26 % in SMseas, and 55 % in SMshort. The AMSR-E assimilation significantly reduced the total ubMSE at every site, with an average reduction of 33 %. Of this ubMSE reduction, 37 % occurred in SMlong, 24 % in SMseas, and 38 % in SMshort. For root-zone soil moisture, in situ observations were available at one site only, and the near-surface and root-zone results were very similar at this site. These results suggest that, in addition to the well-reported improvements in SMshort, assimilating a sufficiently long soil moisture data record can also improve the model representation of important long-term events, such as droughts. The improved agreement between the modeled and in situ SMseas is harder to interpret, given that mean seasonal cycle errors are systematic, and systematic errors are not typically targeted by (bias-blind) data assimilation. Finally, the use of 1-year subsets of the AMSR-E and Catchment soil moisture for estimating the observation-bias correction (rescaling) parameters is investigated. It is concluded that when only 1 year of data are available, the associated uncertainty in the rescaling parameters should not greatly reduce the average benefit gained from data assimilation, although locally and in extreme years there is a risk of increased errors.

Languages Past and Present: Archaeological Approaches to the Appearance of Northern Iroquoian Speakers in the Lower Great Lakes Region of North America

2008 ◽  
Vol 73 (3) ◽  
pp. 441-463 ◽  
Author(s):  
Scott W. J. Martin
Keyword(s):  
Great Lakes ◽  
First Nations ◽  
Great Lakes Region ◽  
Southern Ontario ◽  
Past Half Century ◽  
Archaeological Materials ◽  
First Millennium ◽  
Spread Of Agriculture ◽  
Demic Diffusion

Archaeological accounts of the spread of agriculture tend to favor either (im)migration/demic diffusion or in situ development/stimulus diffusion. Having moved away from the early twentieth-century's community-wide migration model for Iroquoian origins in the Lower Great Lakes region and southern Ontario in particular, orthodox archaeological belief over the past half-century had come to place Northern Iroquoian speakers in the area since at least 2,000 years ago and likely much earlier. In what appear to be modified versions of the older migrationist arguments, contemporary thought within archaeology once more seems to allow that wholesale relocations were responsible for bringing farming into the region. It has been suggested, for example, that Northern Iroquoian speakers entered southern Ontario as recently as the early or middle centuries of the first millennium A.D. In this paper, I recount the routes this debate has taken and show that the appearance of maize (Zea mays) agriculture, alongside a few other materials, has come to be bound up with documenting the arrival of Northern Iroquoian-speaking communities. I conclude by reiterating the cautions advised by a number of researchers for how we read past ethnicity from archaeological materials and the role this plays in contemporary political discourse between First Nations and others.

scholarly journals Evaluation of SMAP Level 2, 3, and 4 Soil Moisture Datasets over the Great Lakes Region

2020 ◽  
Vol 12 (22) ◽  
pp. 3785
Author(s):  
Xiaoyong Xu
Keyword(s):  
Soil Moisture ◽  
Great Lakes ◽  
Root Zone ◽  
Evaluation Studies ◽  
Reference Network ◽  
Great Lakes Region ◽  
Sparse Network ◽  
Level 2 ◽  
The U.S

Satellite sensor systems for soil moisture measurements have been continuously evolving. The Soil Moisture Active Passive (SMAP) mission represents one of the latest advances in this regard. Thus far, much of our knowledge of the accuracy of SMAP soil moisture over the Great Lakes region of North America has originated from evaluation studies using in situ data from the U.S. Department of Agriculture (USDA) Natural Resources Conservation Service Soil Climate Analysis Network and/or the U.S. Climate Reference Network, which provide only several in situ sensor stations for this region. As such, these results typically underrepresent the accuracy of SMAP soil moisture in this region, which is characterized by a relatively large soil moisture variability and is one of the least studied regions. In this work, SMAP Level 2‒4 soil moisture products: SMAP/Sentinel-1 L2 Radiometer/Radar Soil Moisture (SPL2SMAP_S), SMAP Enhanced L3 Radiometer Soil Moisture (SPL3SMP_E), and SMAP L4 Surface and Root-Zone Soil Moisture Analysis Update (SPL4SMAU) are evaluated over the southern portion of the Great Lakes region using in situ measurements from Michigan State University’s Enviro-weather Automated Weather Station Network. The unbiased root-mean-square error (ubRMSE) values for both SPL4SMAU surface and root zone soil moisture estimates are below 0.04 m3 m−3 at the 36-km scale, with an average ubRMSE of 0.045 m3 m−3 (0.037 m3 m−3) for the surface (root-zone) soil moisture against the sparse network. The ubRMSE values for SPL3SMP_E a.m. (i.e., descending overpasses) soil moisture retrievals are close to or below 0.04 m3 m−3 at the 36-km scale, with an average ubRMSE of ~0.06 m3 m−3 against the sparse network. The average ubRMSE values are ~0.05‒0.06 m3 m−3 for high-resolution SPL2SMAP_S soil moisture retrievals against the sparse network, with the skill of the baseline algorithm-based soil moisture retrievals exceeding that of the optional algorithm-based counterparts. Clearly, the skill of SPL4SMAU surface soil moisture exceeds that of the SPL3SMP_E and SPL2SMAP_S soil moisture retrievals.

scholarly journals Lagrangian Perspective on the Origins of Denmark Strait Overflow

2020 ◽  
Vol 50 (8) ◽  
pp. 2393-2414
Author(s):  
Atousa Saberi ◽  
Thomas W. N. Haine ◽  
Renske Gelderloos ◽  
M. Femke de Jong ◽  
Heather Furey ◽  
...  
Keyword(s):  
North Atlantic ◽  
Meridional Overturning Circulation ◽  
Near Surface ◽  
The North ◽  
East Greenland Current ◽  
Nao Index ◽  
Denmark Strait ◽  
Meridional Overturning ◽  
In Situ Observations

AbstractThe Denmark Strait Overflow (DSO) is an important contributor to the lower limb of the Atlantic meridional overturning circulation (AMOC). Determining DSO formation and its pathways is not only important for local oceanography but also critical to estimating the state and variability of the AMOC. Despite prior attempts to understand the DSO sources, its upstream pathways and circulation remain uncertain due to short-term (3–5 days) variability. This makes it challenging to study the DSO from observations. Given this complexity, this study maps the upstream pathways and along-pathway changes in its water properties, using Lagrangian backtracking of the DSO sources in a realistic numerical ocean simulation. The Lagrangian pathways confirm that several branches contribute to the DSO from the north such as the East Greenland Current (EGC), the separated EGC (sEGC), and the North Icelandic Jet (NIJ). Moreover, the model results reveal additional pathways from south of Iceland, which supplied over 16% of the DSO annually and over 25% of the DSO during winter of 2008, when the NAO index was positive. The southern contribution is about 34% by the end of March. The southern pathways mark a more direct route from the near-surface subpolar North Atlantic to the North Atlantic Deep Water (NADW), and needs to be explored further, with in situ observations.

scholarly journals The Inconsistent Pairs between In Situ Observations of Near Surface Salinity and Multiple Remotely Sensed Salinity Data

2021 ◽  
Author(s):  
Hengqian Yan ◽  
Huizan Wang ◽  
Ren Zhang ◽  
Senliang Bao ◽  
Jian Chen ◽  
...  
Keyword(s):  
Remotely Sensed ◽  
Surface Salinity ◽  
Near Surface ◽  
Salinity Data ◽  
In Situ Observations

Observations of the Tasman Sea Internal Tide Beam

2018 ◽  
Vol 48 (6) ◽  
pp. 1283-1297 ◽  
Author(s):  
Amy F. Waterhouse ◽  
Samuel M. Kelly ◽  
Zhongxiang Zhao ◽  
Jennifer A. MacKinnon ◽  
Jonathan D. Nash ◽  
...  
Keyword(s):  
Plane Wave ◽  
Energy Flux ◽  
Internal Tide ◽  
Surface Displacement ◽  
Internal Tides ◽  
Near Surface ◽  
Tasman Sea ◽  
Stationary Energy ◽  
In Situ Observations

AbstractLow-mode internal tides, a dominant part of the internal wave spectrum, carry energy over large distances, yet the ultimate fate of this energy is unknown. Internal tides in the Tasman Sea are generated at Macquarie Ridge, south of New Zealand, and propagate northwest as a focused beam before impinging on the Tasmanian continental slope. In situ observations from the Tasman Sea capture synoptic measurements of the incident semidiurnal mode-1 internal-tide, which has an observed wavelength of 183 km and surface displacement of approximately 1 cm. Plane-wave fits to in situ and altimetric estimates of surface displacement agree to within a measurement uncertainty of 0.3 cm, which is the same order of magnitude as the nonstationary (not phase locked) mode-1 tide observed over a 40-day mooring deployment. Stationary energy flux, estimated from a plane-wave fit to the in situ observations, is directed toward Tasmania with a magnitude of 3.4 ± 1.4 kW m−1, consistent with a satellite estimate of 3.9 ± 2.2 kW m−1. Approximately 90% of the time-mean energy flux is due to the stationary tide. However, nonstationary velocity and pressure, which are typically 1/4 the amplitude of the stationary components, sometimes lead to instantaneous energy fluxes that are double or half of the stationary energy flux, overwhelming any spring–neap variability. Despite strong winds and intermittent near-inertial currents, the parameterized turbulent-kinetic-energy dissipation rate is small (i.e., 10−10 W kg−1) below the near surface and observations of mode-1 internal tide energy-flux convergence are indistinguishable from zero (i.e., the confidence intervals include zero), indicating little decay of the mode-1 internal tide within the Tasman Sea.

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