Long-Term (1946-2008) record of 35,580 measurements of daily mean air temperatures in three meteorological stations (Dan, Dafna, Kfar Blum) in the Hula Valley, within the drainage basin of Lake Kinneret (Israel) was s...Long-Term (1946-2008) record of 35,580 measurements of daily mean air temperatures in three meteorological stations (Dan, Dafna, Kfar Blum) in the Hula Valley, within the drainage basin of Lake Kinneret (Israel) was statistically evaluated. Temperature decline after the drainage of the old Lake Hula and adjacent wetlands (1958) and increase from the mid 1980’s, after the implementation of the Hula Project aimed at continuous land green cover were verified. It was suggested that those regional climate changes were due to the change of Albedo levels: lower when land was water covered and higher after regional drainage followed by a decline when vegetation cover became intensive and continuous. Decline of Albedo levels led to higher air temperature and vice versa.展开更多
Until 1957 most of the Hula Valley was occupied by swampy wetland covered by dense vegetation and old Lake Hula. Organic matter was accumulated in the bottom, decomposed under anoxic conditions creating Peat material....Until 1957 most of the Hula Valley was occupied by swampy wetland covered by dense vegetation and old Lake Hula. Organic matter was accumulated in the bottom, decomposed under anoxic conditions creating Peat material. The wetland and the old lake were drained and the land-use was converted into agricultural development. Nutrients migrations from the Hula Valley through the headwater discharges carrying nutrients, where nitrogen enhancement is critical, significantly affecting water quality in down-stream Lake Kinneret. The fate of the Hula originated nutrients is partly known whilst fate of the others which might be probably a threat on the Kinneret water quality is unknown. The hypsometrical and spatial distribution of the Hula Valley originated nutrients within three depths level was indicated: shallowest level of surface water, intermediate level of underground water table and the deepest level of Lignite waters. The Hypsometrical and spatial distribution and regional origin of the nutrient in the Hula Valley was defined. Organic Nitrogen, Sulfate and Nitrates are mostly Hula Valley originated nutrients whilst most of the Phosphorus externally contributed to Lake Kinneret originate outside the Hula Valley. An underground north-south Hydrological gradient and nutrient migration along was indicated. It is suggested that an underground plastic barrier do not totally prevent horizontal nutrient migration. Hypsometrical downward migrated nutrients probably accumulate within the “Lignite” depth level. Management policy of increasing Peat Soil moisture, is recommended.展开更多
文摘Long-Term (1946-2008) record of 35,580 measurements of daily mean air temperatures in three meteorological stations (Dan, Dafna, Kfar Blum) in the Hula Valley, within the drainage basin of Lake Kinneret (Israel) was statistically evaluated. Temperature decline after the drainage of the old Lake Hula and adjacent wetlands (1958) and increase from the mid 1980’s, after the implementation of the Hula Project aimed at continuous land green cover were verified. It was suggested that those regional climate changes were due to the change of Albedo levels: lower when land was water covered and higher after regional drainage followed by a decline when vegetation cover became intensive and continuous. Decline of Albedo levels led to higher air temperature and vice versa.
文摘Until 1957 most of the Hula Valley was occupied by swampy wetland covered by dense vegetation and old Lake Hula. Organic matter was accumulated in the bottom, decomposed under anoxic conditions creating Peat material. The wetland and the old lake were drained and the land-use was converted into agricultural development. Nutrients migrations from the Hula Valley through the headwater discharges carrying nutrients, where nitrogen enhancement is critical, significantly affecting water quality in down-stream Lake Kinneret. The fate of the Hula originated nutrients is partly known whilst fate of the others which might be probably a threat on the Kinneret water quality is unknown. The hypsometrical and spatial distribution of the Hula Valley originated nutrients within three depths level was indicated: shallowest level of surface water, intermediate level of underground water table and the deepest level of Lignite waters. The Hypsometrical and spatial distribution and regional origin of the nutrient in the Hula Valley was defined. Organic Nitrogen, Sulfate and Nitrates are mostly Hula Valley originated nutrients whilst most of the Phosphorus externally contributed to Lake Kinneret originate outside the Hula Valley. An underground north-south Hydrological gradient and nutrient migration along was indicated. It is suggested that an underground plastic barrier do not totally prevent horizontal nutrient migration. Hypsometrical downward migrated nutrients probably accumulate within the “Lignite” depth level. Management policy of increasing Peat Soil moisture, is recommended.
