Noah Knowles
Noah Knowles is a Research Hydrologist with the USGS Water Resources Mission Area.
Science and Products
Filter Total Items: 27
High-Resolution Digital Terrain Models of the Sacramento/San Joaquin Delta Region, California
The U.S. Geological Survey (USGS) Western Region Geographic Science Center, in conjunction with the USGS Water Resources Western Branch of Regional Research, has developed a high-resolution elevation dataset covering the Sacramento/San Joaquin Delta region of California. The elevation data were compiled photogrammically from aerial photography (May 2002) with a scale of 1:15,000. The resulting dat
Authors
Tom Coons, Christopher E. Soulard, Noah Knowles
Temporal downscaling of decadal sediment load estimates to a daily interval for use in hindcast simulations
In this study we used hydrologic proxies to develop a daily sediment load time-series, which agrees with decadal sediment load estimates, when integrated. Hindcast simulations of bathymetric change in estuaries require daily sediment loads from major tributary rivers, to capture the episodic delivery of sediment during multi-day freshwater flow pulses. Two independent decadal sediment load estimat
Authors
N. K. Ganju, N. Knowles, D. H. Schoellhamer
Trends in snowfall versus rainfall in the western United States
The water resources of the western United States depend heavily on snowpack to store part of the wintertime precipitation into the drier summer months. A well-documented shift toward earlier runoff in recent decades has been attributed to 1) more precipitation falling as rain instead of snow and 2) earlier snowmelt. The present study addresses the former, documenting a regional trend toward smalle
Authors
N. Knowles, M. D. Dettinger, D.R. Cayan
Snowmelt discharge characteristics Sierra Nevada, California
Alpine snow is an important water resource in California and the western U.S. Three major features of alpine snowmelt are the spring pulse (the first surge in snowmelt-driven river discharge in spring), maximum snowmelt discharge, and base flow (low river discharge supported by groundwater in fall). A long term data set of hydrologic measurements at 24 gage locations in 20 watersheds in the Sierra
Authors
David Peterson, Richard Smith, Iris Stewart, Noah Knowles, Chris Soulard, Stephen Hager
Recent changes toward earlier springs---early signs of climate warming in western North America
No abstract available.
Authors
D. Cayan, M. Dettinger, I. Stewart, N. Knowles
Climate anomalies generate an exceptional dinoflagellate bloom in San Francisco Bay
We describe a large dinoflagellate bloom, unprecedented in nearly three decades of observation, that developed in San Francisco Bay (SFB) during September 2004. SFB is highly enriched in nutrients but has low summer‐autumn algal biomass because wind stress and tidally induced bottom stress produce a well mixed and light‐limited pelagic habitat. The bloom coincided with calm winds and record high a
Authors
J. E. Cloern, T.S. Schraga, C.B. Lopez, N. Knowles, Labiosa R. Grover, R. Dugdale
Elevational dependence of projected hydrologic changes in the San Francisco Estuary and watershed
California's primary hydrologic system, the San Francisco Estuary and its upstream watershed, is vulnerable to the regional hydrologic consequences of projected global climate change. Previous work has shown that a projected warming would result in a reduction of snowpack storage leading to higher winter and lower spring-summer streamflows and increased spring-summer salinities in the estuary. The
Authors
N. Knowles, D.R. Cayan
Climate science issues and needs of the CALFED Bay-Delta Program
No abstract available.
Authors
M. D. Dettinger, W.A. Bennett, D.R. Cayan, J. Florsheim, M. Hughes, B. L. Ingram, A.D. Jassby, N. Knowles, F. Malamud, D.H. Peterson, K. Redmond, L. Smith
Potential effects of global warming on the Sacramento/San Joaquin watershed and the San Francisco estuary
California's primary hydrologic system, the San Francisco estuary and its upstream watershed, is vulnerable to the regional hydrologic consequences of projected global climate change. Projected temperature anomalies from a global climate model are used to drive a combined model of watershed hydrology and estuarine dynamics. By 2090, a projected temperature increase of 2.1°C results in a loss of ab
Authors
Noah Knowles, Daniel R. Cayan
Natural and management influences on freshwater inflows and salinity in the San Francisco Estuary at monthly to interannual scales
Understanding the processes controlling the physics, chemistry, and biology of the San Francisco Estuary and their relation to climate variability is complicated by the combined influence on freshwater inflows of natural variability and upstream management. To distinguish these influences, alterations of estuarine inflow due to major reservoirs and freshwater pumping in the watershed were inferred
Authors
Noah Knowles
Ancient blue oaks reveal human impact on San Francisco Bay salinity
San Francisco Bay is one of the most important estuaries on the west coast of the Americas. Its water quality is controlled primarily by streamflow from the Sacramento and San Joaquin rivers. In fact, freshwater inflow from the Sacramento-San Joaquin Delta explains 86% of the salinity variability at the mouth of the San Francisco Bay estuary [Peterson et al., 1989]. The massive diversion of stream
Authors
David W. Stahle, Matthew D. Therrell, Malcolm K. Cleaveland, Daniel R. Cayan, Michael D. Dettinger, Noah Knowles
Modeling the hydroclimatology of the San Francisco Bay-Delta estuary and watershed
No abstract available.
Authors
Noah Knowles
Science and Products
Filter Total Items: 27
High-Resolution Digital Terrain Models of the Sacramento/San Joaquin Delta Region, California
The U.S. Geological Survey (USGS) Western Region Geographic Science Center, in conjunction with the USGS Water Resources Western Branch of Regional Research, has developed a high-resolution elevation dataset covering the Sacramento/San Joaquin Delta region of California. The elevation data were compiled photogrammically from aerial photography (May 2002) with a scale of 1:15,000. The resulting dat
Authors
Tom Coons, Christopher E. Soulard, Noah Knowles
Temporal downscaling of decadal sediment load estimates to a daily interval for use in hindcast simulations
In this study we used hydrologic proxies to develop a daily sediment load time-series, which agrees with decadal sediment load estimates, when integrated. Hindcast simulations of bathymetric change in estuaries require daily sediment loads from major tributary rivers, to capture the episodic delivery of sediment during multi-day freshwater flow pulses. Two independent decadal sediment load estimat
Authors
N. K. Ganju, N. Knowles, D. H. Schoellhamer
Trends in snowfall versus rainfall in the western United States
The water resources of the western United States depend heavily on snowpack to store part of the wintertime precipitation into the drier summer months. A well-documented shift toward earlier runoff in recent decades has been attributed to 1) more precipitation falling as rain instead of snow and 2) earlier snowmelt. The present study addresses the former, documenting a regional trend toward smalle
Authors
N. Knowles, M. D. Dettinger, D.R. Cayan
Snowmelt discharge characteristics Sierra Nevada, California
Alpine snow is an important water resource in California and the western U.S. Three major features of alpine snowmelt are the spring pulse (the first surge in snowmelt-driven river discharge in spring), maximum snowmelt discharge, and base flow (low river discharge supported by groundwater in fall). A long term data set of hydrologic measurements at 24 gage locations in 20 watersheds in the Sierra
Authors
David Peterson, Richard Smith, Iris Stewart, Noah Knowles, Chris Soulard, Stephen Hager
Recent changes toward earlier springs---early signs of climate warming in western North America
No abstract available.
Authors
D. Cayan, M. Dettinger, I. Stewart, N. Knowles
Climate anomalies generate an exceptional dinoflagellate bloom in San Francisco Bay
We describe a large dinoflagellate bloom, unprecedented in nearly three decades of observation, that developed in San Francisco Bay (SFB) during September 2004. SFB is highly enriched in nutrients but has low summer‐autumn algal biomass because wind stress and tidally induced bottom stress produce a well mixed and light‐limited pelagic habitat. The bloom coincided with calm winds and record high a
Authors
J. E. Cloern, T.S. Schraga, C.B. Lopez, N. Knowles, Labiosa R. Grover, R. Dugdale
Elevational dependence of projected hydrologic changes in the San Francisco Estuary and watershed
California's primary hydrologic system, the San Francisco Estuary and its upstream watershed, is vulnerable to the regional hydrologic consequences of projected global climate change. Previous work has shown that a projected warming would result in a reduction of snowpack storage leading to higher winter and lower spring-summer streamflows and increased spring-summer salinities in the estuary. The
Authors
N. Knowles, D.R. Cayan
Climate science issues and needs of the CALFED Bay-Delta Program
No abstract available.
Authors
M. D. Dettinger, W.A. Bennett, D.R. Cayan, J. Florsheim, M. Hughes, B. L. Ingram, A.D. Jassby, N. Knowles, F. Malamud, D.H. Peterson, K. Redmond, L. Smith
Potential effects of global warming on the Sacramento/San Joaquin watershed and the San Francisco estuary
California's primary hydrologic system, the San Francisco estuary and its upstream watershed, is vulnerable to the regional hydrologic consequences of projected global climate change. Projected temperature anomalies from a global climate model are used to drive a combined model of watershed hydrology and estuarine dynamics. By 2090, a projected temperature increase of 2.1°C results in a loss of ab
Authors
Noah Knowles, Daniel R. Cayan
Natural and management influences on freshwater inflows and salinity in the San Francisco Estuary at monthly to interannual scales
Understanding the processes controlling the physics, chemistry, and biology of the San Francisco Estuary and their relation to climate variability is complicated by the combined influence on freshwater inflows of natural variability and upstream management. To distinguish these influences, alterations of estuarine inflow due to major reservoirs and freshwater pumping in the watershed were inferred
Authors
Noah Knowles
Ancient blue oaks reveal human impact on San Francisco Bay salinity
San Francisco Bay is one of the most important estuaries on the west coast of the Americas. Its water quality is controlled primarily by streamflow from the Sacramento and San Joaquin rivers. In fact, freshwater inflow from the Sacramento-San Joaquin Delta explains 86% of the salinity variability at the mouth of the San Francisco Bay estuary [Peterson et al., 1989]. The massive diversion of stream
Authors
David W. Stahle, Matthew D. Therrell, Malcolm K. Cleaveland, Daniel R. Cayan, Michael D. Dettinger, Noah Knowles
Modeling the hydroclimatology of the San Francisco Bay-Delta estuary and watershed
No abstract available.
Authors
Noah Knowles