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1. A Model for Mid‐Holocene—Present U.S. Mid‐Atlantic Piedmont River Corridor Sediment Budgets Fit... 2023

   https://ncsu.summon.serialssolutions.com/2.0.0/link/0/eLvHCXMwpV3NTtwwELZauPRSgYpUWkA-0NMqbOKExJYQUvhZFvq36i7qMYrjGFZCgEL2wgnxBBz6hDxJZxx7s4tWVaterMjJOtbMt-PJeOYzIdvaL5DEBb5NkpB5kZC5x1WkvSL3o8CXUodB8SKYc-1qYRZmsXf_W7XQB8rFUtl_UO90UOiAa1AytKBmaP9K0ak5z8yUIXa-wttd9kIfzFoBlsx1RIOm0qhzvjPcmXsyra9AvpgjD_4ozLvu_MBsDbAVVTVWMOwQVjiTNHAwURdlfdfpjWt0Wg217dhwXsOvj5oyt0W-7kV5c-sAYemFkGY5r0x-fKXzFl-D8f39pG72g2yZhA1KsDa9bWHwsQmmtWlKYNxYEAsPo6jNOjTbZ42vs86Mz8LQX2j2fYasqTiRs57hQhft8ua29PvpMBsc9bIvp98-vybLLBEcU0CD74fTmBweQiLMBvl0erZWAl7QnR1-3ouZX8SNZzJaIW-tmGnaQGOVvCqv35HHlBpYUIAFBWU_Pzw5QDw__LJQoAgFe3fvct_hYK97uU8dFqjBAnVYoA4L1GKBAhZofUPnsEARC2vkvHc8Oux79rwNL2c8qD2ttPZVKINAKAYSCEvJtS5kshvrJAZvRyVIWpGoCLff4UMXveGwVKXUUayECt8TCurKwcXRccmTSGuw_mGxKyTSUnKZi2KdfHKCy24bPpXM5EEwkc0KeJ1sOKlm9s92lzHOwd_GAxI-_Pn2R_KmReUGWaqrSblJltCebBmVQ5uMTraQFfbnb2jEcjA

   Pizzuto, J. E.

   Journal Of Geophysical Research. Earth Surface, Vol. 128, Issue 10.

   Abstract Fluvial sediment transport and deposition shapes river, floodplain, and estuarine systems but also can create water quality problems, which in some cases motivates efforts to reduce hillsl... Read more

   Abstract Fluvial sediment transport and deposition shapes river, floodplain, and estuarine systems but also can create water quality problems, which in some cases motivates efforts to reduce hillslope erosion. However, watershed management efforts rarely consider the fate of eroded sediments and the time scale of transport to estuaries. This study presents a modeling approach to estimate regionally averaged floodplain deposition, erosion, and sediment flux for the mid‐Atlantic U.S. caused by changing forest cover, urban development, and milldam construction. Regional regression equations estimate discharge at 3‐month intervals, and (temporally invariant) channel width and slope. Sediment concentrations are determined from a rating curve (defined for modern conditions by gaging‐station data). Tuning the model to floodplain stratigraphic data suggests that‐sediment concentrations prior to European colonization (i.e., before ∼1750) were 5%–8% of those prevailing today, while legacy (1750–1950) sediment concentrations were 25%–35% of present values. The calibration process, however, is only partly successful for the period before 1750 due to the limited number of older dated samples available. Nonetheless, the model accurately reproduces the observed age distribution of floodplain deposits. Computed sediment‐budget components increase monotonically from before 1750 to the present, and the ratio of budget components remains similar from one time period to the next. The model also predicts that millennial timescales are needed for mid‐Atlantic floodplains to equilibrate following a change in sediment regime, a finding with important implications for river corridor and watershed restoration planning. Plain Language Summary Sediment carried by rivers creates water‐quality problems in estuaries downstream. One solution is to reduce erosion from upland hillslopes. Eroded sediment, however, is rarely transported directly to estuaries, but is often deposited in floodplains, a process that is rarely considered in watershed management. This study quantifies floodplain deposition and erosion in the mid‐Atlantic region caused by changing forest cover, urban development, and mill‐dam construction. The model is adjusted to accurately reproduce observed floodplain deposits from three time periods: prior to European colonization (before 1750), legacy (from 1750 to 1950), and modern (1950–2017). The calibration process, however, is only partly successful for the period before 1750 due to the limited number of older dated samples available. The model predicts that the rates of sediment transport and floodplain sedimentation and erosion have increased through time from before 1750 to the present. When deposited, sediment “awaits” on floodplains before being remobilized for tens, hundreds, and even thousands of years, indicating that long time periods will be needed before estuaries downstream can realize the full intended benefits of watershed restoration. Key Points A model driven by land‐use changes and tuned to stratigraphic data predicts floodplain sediment budgets All sediment‐budget components have increased through time, and millennia are needed to reach equilibrium after disturbances Well‐dated stratigraphic sections, currently unavailable, are needed to fully calibrate the model for conditions preceding 1750 Read less

   Journal Article  |  Full Text Online

2. A 2,300-year-long annually resolved record of the South American summer monsoon from the Peruvian... 2011

   https://ncsu.summon.serialssolutions.com/2.0.0/link/0/eLvHCXMwnV1Lb9QwEB7RcuGC2vJoaImMxKFIuJvYSewcV1ULQqJUqAhxihzHLpW2yWrTrdR_37Gd7LIVXMghF48dyzOTmbHH3wC8t4l2IC4YmwjOaFbWisoms1SrJEuTurY81ZubOZCPd2F80r6ur4_b2c1xe_3b51bOb_RkzBObXHw94Q5voCwmW7AleDaG6CukXRnunTD8_WYsG_F8BJ_MW9W7tAAuMEpJpAcCzvFxxX_-sEohMdGhnSL93zzPxwmUIXXSW6SzHXg-uJJkGqa8C09Muwe7g7L25GhAlP7wAq6mhH3kSULvUa7prGuvSMAind0TDLe72Z1pSNiuIZ0l6BMSX1qPjOc5xMmrWRCU2b7rWuIupXiyC7NY3qGEkWnbmP4l_Dg7vTz5TIcKC1S5QgYUjbO2SgsjPBCZQdaUwlUQY0KniRLcZBhBqbpodNMoyYxtFK9VkktepFIxvg8EDZxCo2YLI0VmLeo713lZOyBCWatSR3A0Lm01DwgalT_5FrxyC1ytGRLBK7_0KzqGH0IXNo9g35Ou-8uKpZXE5ggORv5Ug_r1lSxkiRNPigjerVpRb9xhiGpNt_RflRLD8wJHIP-gwWHcOaUb5nVg-Hpmg-BEIDZEYUXgYLs3W1CaPXz3IL1v_rvnATwLO9s5ZdkhbN8uluYtbLs7HzFqxOWn2KGd_ozh6ZfT82-_Yp_niu_v59PY68oDcGoR6Q

   Bird, Broxton W.; Abbott, Mark B.; Vuille, Mathias; Rodbell, Donald T....

   Proceedings Of The National Academy Of Sciences Pnas, Vol. 108, Issue 21, pp. 8583 - 8588.

   Decadal and centennial mean state changes in South American summer monsoon (SASM) precipitation during the last 2,300 years are detailed using an annually resolved authigenic calcite record of prec... Read more

   Decadal and centennial mean state changes in South American summer monsoon (SASM) precipitation during the last 2,300 years are detailed using an annually resolved authigenic calcite record of precipitation δ¹⁸O from a varved lake in the Central Peruvian Andes. This unique sediment record shows that δ¹⁸O peaked during the Medieval Climate Anomaly (MCA) from A.D. 900 to 1100, providing evidence that the SASM weakened considerably during this period. Minimum δ¹⁸O values occurred during the Little Ice Age (LIA) between A.D. 1400 and 1820, reflecting a prolonged intensification of the SASM that was regionally synchronous. After the LIA, δ¹⁸O increased rapidly, particularly during the current warm period (CWP; A.D. 1900 to present), indicating a return to reduced SASM precipitation that was more abrupt and sustained than the onset of the MCA. Diminished SASM precipitation during the MCA and CWP tracks reconstructed Northern Hemisphere and North Atlantic warming and a northward displacement of the Intertropical Convergence Zone (ITCZ) over the Atlantic, and likely the Pacific. Intensified SASM precipitation during the LIA follows reconstructed Northern Hemisphere and North Atlantic cooling, El Niño-like warming in the Pacific, and a southward displacement of the ITCZ over both oceans. These results suggest that SASM mean state changes are sensitive to ITCZ variability as mediated by Western Hemisphere tropical sea surface temperatures, particularly in the Atlantic. Continued Northern Hemisphere and North Atlantic warming may therefore help perpetuate the recent reductions in SASM precipitation that characterize the last 100 years, which would negatively impact Andean water resources. Read less

   Journal Article  |  Full Text Online

3. Abrupt drainage cycles of the Fennoscandian Ice Sheet 2013

   https://ncsu.summon.serialssolutions.com/2.0.0/link/0/eLvHCXMwnV1Lb9QwEB6x5cIFUV4NlJVBHMoh3cR2Yue4qlq1CAqi9MApsp2YrUSzq-4uEv-eGedRpeqplxwSx56M5xmPPwN89IkjEBfMTZTgsSysiXUlfexMItPEWi9SN_6ZA1m_FyYU7Tt7ddj8uT5srhahtnJ17WZ9ndjs-9cjkQuldDKbwEQJ2afoA9KubvedcDS_kssez0eJ2aoxa4JTQOOQo9sjIGCR5QXP5cgrTbxZ4nVBlZFtkSJVTJo1Ms23p10QEir2dV9Uere4soWeCt7q5Bk87cJMNm8_Zxce1c1z2O0Uec0OOrTpTy8gm9ub7WrDKjorAo0Lc_-IAWzpGcaGDKW4WSJNDckRO3M1u1jU9eYlXJ4c_zw6jbuzFGKDEc8mNi7JktTaCt1_hSlMYiqvdJGif86MtdJyWxtthMxcWonKal1wb4Q2xkshuRN7wNCVGXRfPq-1kt6jZguXFZYgB7U1hYvgoGdiuWqxMsqwxq1ESewqb1kfwR4yuTS_0ZKVlxeccO5ozRSD1wg-IOeHDgj--nT-paR7icT8TEj9N43gVZiYoRmanoKytwimo5kaGnCFwZ7KFY4caBkIJApVmeeaR7DfT2fZaTLSLJBkDIt0HsH74THqIC2smKZebts2BK2Xighet7N_O24nYRGokVyMPnD8BMU-4Hx3Yv7mwW--hSc8nN4hYy72YWdzs63fwQ5tDpnC48_H599-TUMRLF5_nM-nQZH-A72MGJM

   Soulet, Guillaume; Ménot, Guillemette; Bayon, Germain; Rostek, Frauke...

   Proceedings Of The National Academy Of Sciences Pnas, Vol. 110, Issue 17, pp. 6682 - 6687.

   Continental ice sheets are a key component of the Earth’s climate system, but their internal dynamics need to be further studied. Since the last deglaciation, the northern Eurasian Fennoscandian Ic... Read more

   Continental ice sheets are a key component of the Earth’s climate system, but their internal dynamics need to be further studied. Since the last deglaciation, the northern Eurasian Fennoscandian Ice Sheet (FIS) has been connected to the Black Sea (BS) watershed, making this basin a suitable location to investigate former ice-sheet dynamics. Here, from a core retrieved in the BS, we combine the use of neodymium isotopes, high-resolution elemental analysis, and biomarkers to trace changes in sediment provenance and river runoff. We reveal cyclic releases of meltwater originating from Lake Disna, a proglacial lake linked to the FIS during Heinrich Stadial 1. Regional interactions within the climate–lake–FIS system, linked to changes in the availability of subglacial water, led to abrupt drainage cycles of the FIS into the BS watershed. This phenomenon raised the BS water level by ∼100 m until the sill of the Bosphorus Strait was reached, flooding the vast northwestern BS shelf and deeply affecting the hydrology and circulation of the BS and, probably, of the Marmara and Aegean Seas. Read less

   Journal Article  |  Full Text Online

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